Die Schwalbe

49 problem(s) found in 8801 milliseconds (displaying 49 problem(s)). [COMMENTDATE>=20200919 AND NOT K='Hilfsrückzüger' AND NOT K='Abzugsmatt' AND S='PDB Website'] [download as LaTeX]

1 - P1304585
Mikhail Popov
842v Gazeta Czestochowska 16/04/1968
Version PDB Website 23/06/2015
2. Lob
Version Marcin Banaszek
P1304585
(8+10) C+
s#2
1. Lh8-g7? c6-c5!
1. Tf6xc6? c3xb2+!
1. Sg4-f2,Sg~? c6-c5!
1. d2-d4? c6-c5 2. d4xc5 Da1xb2#,c3xb2#
1. ... e4xd3ep!
1. b2-b3? a4xb3 2. Tf6xc6 Da1-b2#,b3-b2#,c3xd2#
1. ... c6-c5!

1. b2-b4! c6-c5 2. b4xc5 Da1-b2#,c3xd2#
1. ... a4xb3ep 2. Tf6xc6 Da1-b2#,b3-b2#,c3xd2#
play all play one stop play next play all
Korrekte Version zu P1304584.
Anton Baumann: vergl. P1305210 (2024-02-19)
comment

Genre: s#
Computer test: Popeye Windows-32Bit v4.61 (1668 MB)
FEN: 7B/8/2p2R2/8/p3p1N1/P1p1N3/pPpPp3/qbK1k3
Input: Marcin Banaszek, 2015-06-23
Last update: Marcin Banaszek, 2015-11-22 more...
2 - P1323914
Andrew Buchanan
PDB Website 14/08/2016
P1323914
(16+15) C+
a) White to move. Last move?
b) KBP in 4.0
b) 1. f4 Sc6 2. Kf2 Se5 3. Kg3 Sg4 4. Kxg4 Tb8
a) R: 1. Ta8-b8
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See also: P1012898 & P1388527
Henrik Juel: Even though obvious, the a) solution should be included
a) Ta8-b8 (2016-08-15)
A.Buchanan: Can't get both solutions to be animated here, due to hidden interactions with stipulation text (2021-04-14)
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Keywords: Unique Proof Game, Last Move?, Type B
Genre: Retro
Computer test: C+ Retractor 2.0 Last move? C+ Euclide 1.01 SPG
FEN: 1rbqkbnr/pppppppp/8/8/5PK1/8/PPPPP1PP/RNBQ1BNR
Input: A.Buchanan, 2016-08-13
Last update: A.Buchanan, 2021-04-14 more...
3 - P1374643
James Malcom
PDB Website 14/4/2020
“Egg Five”
P1374643
(5+2)
s#1
(-:
1. hxg8=sB! g7#
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Henrik Juel: Here the extra joke is that the (dummy) pawn can move (2020-04-14)
James Malcom: The newly born black pawn is not a dummy pawn, in my opinion. Unlike the dummy, it still has the right to move foward in principal. Since it is new and has never moved, it sill has the right to make a double-step if allowed, as in Horde Chess (https://lichess.org/variant/horde). (2020-04-14)
Henrik Juel: I see your point, James (2020-04-15)
James Malcom: Seems that Gerd might have missed including pawns promoting to opposite color pawns the new update. I'll email him tomorrow morning. With accordance to the rules, they have 4 first moves as a 7th rank pawn does. (2020-05-03)
Gerd Wilts: Promotions to pawns are now also supported. (2020-05-03)
James Malcom: Many thanks Gerd! (2020-05-03)
A.Buchanan: I had missed these 6 miniatures: they are terrific! Can I ask to replace Sg8 in this one with L so that it's not giving check in the starting position. I guess it's kind of crass though economical to replace with pawn! (2020-10-13)
A.Buchanan: Dummy pawns can in principle move imho: it's just that they're usually blocked by the edge of the board. If one was teleported somewhere else on the board by some mechanism, then they would just start moving. So completely different kind of animal from a dummy, which genuinely cannot move :D (2020-10-13)
comment
Keywords: Joke, Joke promotion, under-promotion (b)
Genre: s#
FEN: 6nk/7P/6PK/6PP/8/8/8/8
Input: James Malcom, 2020-04-14
Last update: James Malcom, 2020-06-02 more...
4 - P1375286
Andrew Buchanan
James Malcom

PDB Website 30/4/2020
P1375286
(6+3)
#2
(-:
1. dxc7ep! b4 2. c8=D,T#

R: 1. ... c8-c6?! and earlier c8=sB?!
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Supersession of P1380851

Superseded by P1380851

The 2018 FIDE laws state: "3.7.2 on its first move the pawn may move as in 3.7.1 or alternatively it may advance two squares along the same file, provided that both squares are unoccupied."

Hence Black's newborn 8th rank pawn, which has never been moved before, reserves the right to commence a double-step on its first move, and likewise White receives the right to capture it en passant as they do with a 7th rank pawn.
Henrik Juel: This un-dummy-pawn is like a pawn created on c8 by the Einstein condition
The retroplay looks wrong, what about 1... d8-d6!? 2.d7-d8=sB!? c6xYb5 (2020-04-30)
James Malcom: That makes much more sense Henrik. I have edited it accordingly. (2020-04-30)
A.Buchanan: You don't like Adrian's (: haha? What about :) then? In heraldic terms, it would be described as "regardant". See 270 on https://www.heraldica.org/cgi-bin/atlas.pl?12. I don't know the word for "non-regardant", which is the default direction for the head, e.g. most of the others on that page.
We could replace wBa6a7 with wSa6, but alas having the 3rd knight is non-thematic & distracting. The other thing I would've liked to do is empty b2 so the promotion is forced to be to D. Such a tiny problem should have precision promotion. Needs more thinking. (2020-05-01)
James Malcom: UPDATE: The position has been edited to have one less piece and a precise queen promotion. (2020-10-12)
A.Buchanan: There is dialogue here which is now orphaned by a change of diagram with new matrix. Suggest we revert to the older diagram and mark it superseded by a new PDB entry here (2020-10-12)
James Malcom: I agree-it is now done. (2020-10-12)
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Keywords: En passant as key, Joke, Joke promotion (b), Tolerated dual promotion (D/T), Promotion (D/T), Superseded by (P1380851)
Genre: 2#, Retro
FEN: k7/PN1N4/PKpP4/1p6/8/8/8/8
Input: James Malcom, 2020-04-30
Last update: A.Buchanan, 2022-09-18 more...
5 - P1375431
James Malcom
PDB Website 3/4/2020
"A Midnight Ride"
Gewidmet Gerd Wilts
P1375431
(6+5)
#3
(-:
1. cxb8=sT! Ta8 2. c7 Tb8,Lb8 3. cxb8=sT#

1. ... bxc6? 2. Dxc6#!
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An old idea of mine finally realized between 12:00 PM and 1:00 PM. Dedicated to Gerd Wilts for his initiation of the update that allows promotion to foreign pieces.
Henrik Juel: 1:00 AM, I guess
With 24 hour notation, between 24 and 01 (2022-02-26)
Henrik Juel: Nice double white promotion to sT (2022-02-26)
comment
Keywords: Joke, Joke promotion (tt)
Genre: 3#
FEN: 1qk1K3/bpP5/1pP1N3/1P6/2Q5/8/8/8
Input: James Malcom, 2020-05-03
Last update: James Malcom, 2022-02-26 more...
6 - P1375777
James Malcom
PDB Website 10/4/2020
nach Josef Cumpe
P1375777
(1+8)
Last two moves?
(-:
R: 1. 0-0-0# a7-a8=sT
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See P1234039
Henrik Juel: Missing Joke keyword, I guess (2020-05-11)
A.Buchanan: Curious that retro a7-a8=sT discomforts the animation still - maybe you should report to Gerd? (I trouble him with enough stuff already - don't want to be the only one emailing him! :-) (2020-05-11)
A.Buchanan: Maybe +sBe7f7 to refute R. ... e8=sK/fxe8=sK :-) Note this "cook" is actually prevented in the original. (2020-05-11)
A.Buchanan: Oops and a more major cook R: 1. Se8/g8-f6+ (2020-05-11)
James Malcom: This problem was only half-finished before I fell asleep. It’s fixed now. (2020-05-11)
A.Buchanan: Great! You could save another piece I think -sLg6, -sBf7, + sDf7. This also removes the obtrusive promotion (2020-05-11)
James Malcom: Yes, that is true. Position edited. (2020-05-11)
James Malcom: I see nothing wrong with fiddling if it improves economy. (2020-05-11)
A.Buchanan: If promotion to Bl unit is allowed, can’t Bl just have played e8xd7+ or g8xh7+? Can replace bPd7 with bR but eliminating bPh7 is more complicated. Need +wPh7 +bPg6h6. And also bRb7 to prevent discovered check by bPc8 prior to e7-e8=bK. I think that’s watertight now! :-) (2020-10-13)
A.Buchanan: The issue is that there are two or three levels of Bl promotion joke: this problem relies on the "basic" joke where black officers can be created. But where's the line to stop us promoting to Bl pawn or king? If we go that far, then a position like this 2kr3K/1r1r1qrR/7p/8/8/8/8/8 is required. Oh dear: sorry to have brought it up :( (2020-10-13)
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Keywords: Castling in the retro play, Promotion in the retro play (t), Rex solus (w), Joke, Joke promotion, Type C
Genre: Retro
FEN: 2kr3K/1p1ppqrp/8/8/8/8/8/8
Input: James Malcom, 2020-05-11
Last update: Alfred Pfeiffer, 2020-10-14 more...
7 - P1380882
James Malcom
Andrew Buchanan

PDB Website 14/10/2020
after Josef Cumpe
P1380882
(2+7)
Last two moves?
(-:
R: 1. ... 0-0-0+ 2. a7-a8=sT
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See P1234039, P1375777 and P1380852.
The joke here is that pawns may promote to *any* unit (friend or enemy; officer, king or pawns).
Henrik Juel: R: 1... 0-0-0+ 2.a7-a8=sT
not 2.e7-e8=sK, because then sTa8 would have moved, and castling not allowed (2020-10-14)
A.Buchanan: Exactly, Henrik. Also: sB on 7th rank could retract to 8th rank, so we need sT instead (2020-10-14)
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Keywords: Last Moves? (2), Type C, Castling in the retro play, Non-standard material (tt), Joke, Joke promotion (t), Promotion in the retro play (t), Minimal, Castling (sg)
Genre: Retro
FEN: 2kr3K/1r1r1qrR/7p/8/8/8/8/8
Input: A.Buchanan, 2020-10-14
Last update: A.Buchanan, 2023-08-15 more...
8 - P1381496
Ryan McCracken
PDB Website 01/10/2004
P1381496
(0+0)
BP in which both sides get their pieces all on squares of the same colour?
1. e3 d6 2. La6 Lh3 3. Lxb7 Lxg2 4. Lxa8 Lxh1 5. Le4 Lf3 6. Lxh7 Lxd1 7. Lxg8 Lxc2 8. Sc3 Lb3 9. Lxf7+ Kxf7 10. axb3 Kf6 11. b4
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A.Buchanan: Improves on P0005367 (2020-11-03)
comment
Keywords: Synthetic problem, Non-Unique Proof Game, Ornament, Superseded by (P1381525)
Genre: Retro
FEN: 8/8/8/8/8/8/8/8
Input: A.Buchanan, 2020-11-03
Last update: A.Buchanan, 2020-11-04 more...
9 - P1381916
James Malcom
PDB Website 14/11/2020
P1381916
(13+9)
s#11
(-:
1. h8=T+! Sh6 2. exd8=K! b3 3. a8=sS! b2 4. b8=sL! La7 5. e4 Lb8 6. e5 La7 7. e6 Lb8 8. e7 La7 9. e8=B! Lb8 10. Ta4 La7 11. Txa7 g4#
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A rather... complicated "joke."
A.Buchanan: If one allows promotion to sB (and there seems no reason to disallow it since promotion to pawn, king and foreign units are allowed) then the problem is cooked. There is no universally agreed notion of how a pawn can move if it starts on the first rank. Does it get a double hop, and if so on which rank? But the problem is unsound in any case. (2022-02-10)
James Malcom: That is if, yes. But I don't think this problem ought to be left as is: a demonstration of the levels of absurdity and tomfoolery old rules used to allow. Promotion to a piece of another color and dummies were loopholes, yes, but promotion to a black pawn was never included, not even implicitly. All pawns are pieces, but not all pieces are pawns. (2022-02-10)
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Keywords: Joke promotion (Ksl), Dummy Pawn, konsekutive Umwandlungen 5 (TKslB), under-promotion key (T), Excelsior white, Golden Age (Dummy Pawn), Illegal position (no wK), Joke
Genre: s#, Fairies
Computer test: Difficult to test at the moment because no engine allows both normal and adversarial promotion.
FEN: 2Rr2n1/PPpBP2P/1pP5/1N4pk/1p4Rb/6pP/4P1P1/1Q6
Input: James Malcom, 2020-11-14
Last update: A.Buchanan, 2023-12-11 more...
10 - P1382808
Ronald Turnbull
Andrew Buchanan

PDB Website 20/01/2012
RT, correction AB
P1382808
(4+12)
h#3
AP
PRA
1. bxc3ep 0-0! (for AP reasons, not 1...Kf2?/Th2? etc) 2. Ta1 Txa1 3. Kc4 Txa4#
1. fxe3ep 0-0! (for AP reasons, not 1...Tf1?/Txh3? etc) b2 Txf3 3. Tc3 Tf4#
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For AP as for anything else, the default meta-convention is PRA before RS. Here we use AP to lock down wK & wTh1, so the last move was R: 1. c2-c4 or 1. e2-e4. There is a different h#3 in either case, beginning with ep and then 0-0.
Chessically corrects P1012059 following discussions. It's doubtful that AP logic works as simplistically described here, so this may still be unsound logically. Nevertheless, might as well fix the chess!
See P1399112, where the two parts each prove that one side of White castling rights remain. If this is correct, and only *one* part is required per castling, this implies that this Turnbull-Buchanan problem doesn’t work. For one part we have solution c_S and tries c_T1 & c_T2. In the other part, solution e_S and tries e_T1 & e_T2. Any of 5 combinations work:
c_S + e_S
c_S + e_T1
c_S + e_T2
c_T1 + e_S
c_T2 + e_S
because they all confirm that White retains castling rights.
Classify this problem as Golden Age because it’s on the wrong side of the evolving standard.
A.Buchanan: Let ??? Indicate respectively that w00, c ep & e ep are ok. Then YYN, YNY, NYN, NNY, NNN are the contenders.
Under PRA we reduce to YYN, YNY & NNN but the last has no solution so not the right paradigm.
Under SPRA with AP we reduce to YYN, YNY. Each considered as a separate part has kind of AP h#3, but I don’t understand how consolidation would take place over PRA anyway
Under RS with AP, we have 2 solutions assuming again that no consolidation. (2022-03-23)
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Keywords: a posteriori (AP) (Type Petrovic - cee), En passant as key (2), Castling (wk), Retro Strategy (RS), Golden Age (AP unconsolidated)
Genre: h#, Retro
Computer test: Forward logic sound by Popeye v4.85 However, seems that AP logic is not sound
FEN: 8/8/8/1nr1n3/ppPkPp2/rp1p1p1p/8/4K2R
Input: A.Buchanan, 2020-12-08
Last update: A.Buchanan, 2023-04-06 more...
11 - P1382819
Vladimir Korolkov
Andrew Buchanan

PDB Website 09/12/2020
VK, version AB
P1382819
(12+14) C+
h#3
1. 0-0 Tf1 2. Txf2 Txf2 3. Kh8 Tf8#
For parity reasons, not 1...0-0?
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Corrects (with a little more functionality) P0001361
Henrik Juel: How does one find the parity of the white moves, with DLSS missing? (2020-12-09)
Henrik Juel: Never mind
If White can castle, then last move was e2-e3, so we know where the missing white men were captured, and the parity is easily found (2020-12-09)
Henrik Juel: Suppose (for contradiction) that both sides may castle
Black has the move, so last move was e2-e3, and [Dd1,Lf1] were captured at home, and [Sb1,Sg1] were captured on e6,d5
The number of white and black moves in the game leading to the diagram are both even, so White should have the move
Conclusion: the castlings are mutually exclusive
In the solution Black must castle to get his king to h8, so White cannot get his Th1 to f1 by castling (2020-12-09)
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Keywords: Parity Argument, Castling (wksk), Castling, mutual exclusive
Genre: h#, Retro
Computer test: C+ Popeye v4.85 + thinking
FEN: 2b1k2r/rpppp1pp/p2n4/3p4/8/4P3/PPPP1PPP/RnB1K2R
Input: A.Buchanan, 2020-12-09
Last update: A.Buchanan, 2020-12-09 more...
12 - P1382844
Hans Gruber
Andrew Buchanan

PDB Website 11/12/2020
HG, version AB
P1382844
(6+6) C+
h=4
1. d1=D g7 2. Dd5 g8=S 3. Db7+ axb7 4. a1=L bxc8=T = patt
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corrected version of P1013759, agreed with composer
Henrik Juel: 1.d1=D g7 2.Dd5 g8=S 3.Db7+ axb7 4.a1=L bxc8=T =
Nice version with just Pe4 as a technical unit preventing cooks (2020-12-10)
comment
Keywords: Allumwandlung
Genre: Fairies
Computer test: C+ Popeye v4.85
FEN: 1Kn5/3k4/P3p1P1/4P3/4P3/8/pp1p4/1N6
Input: A.Buchanan, 2020-12-10
Last update: A.Buchanan, 2021-07-05 more...
13 - P1384837
Joaquim Crusats
corr PDB Website 01/01/2021
P1384837
(10+3)
Add a black pawn inside the clock, then 9.5 moves to the same position but pawnless
a) +sBe5 1. d6 Lxd6 2. e7 Lxe7 3. f6 Lxf6 4. g5 Lxg5 5. f4 Lxf4 6. e3 Lxe3 7. d4 Lxd4 8. c5 Lxc5+ 9. Kxe5 Lb4 10. Ke4+
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Try is bP at "9pm"; actual solution is "12am" i.e. midnight of new year. Note that bL goes clockwise
Greeting card, inspired by the traditional Spanish 12 chimes to welcome the New Year.

Original version was cooked, due to FEN file confusion as composer had to compose it "against the clock" as he had been prioritizing deadline for releasing Problemas. Composing a clock problem "against the clock" is thematic though :D:D:D So there were cooks with +bPb2 or +bPc3
SCHRECKE: +sBe5
1.d6 L:d6 2.e7 L:e7 3.f6 L:f6 4.g5 L:g5 5.f4 L:f4 6.e3 L:e3 7.d4 L:d4 8.c5 L:c5+ 9.K:e5 Lb4 10.Ke4+ (2021-01-02)
A.Buchanan: What engine for C+, pls? (2021-01-02)
SCHRECKE: My brain solved it. (2021-01-03)
A.Buchanan: Ha me too! I will remove the C+ tick I put in anticipation (2021-01-03)
James Malcom: The question is, who's computer is smarter? :) (2021-01-03)
Mario Richter: Without long thinking I put the pawn on e5 for two reasons:
1. it shields the black King against white Bishop a1
2. e5 is the only square with property 1 where it doesn't prevent a White pawn from reaching a dark square.

I did some computer tests with 'rawbats' without noticing that the stipulation has changed [by adding the restriction "inside the clock"], the results being:
- no solution if the black pawn is added outside the diagonal b2-g7
- many solutions if black pawn is added on b2 (since it can promote on a1 or b1 and do all the "pawn elimination work")
- one principal solution if the black pawn is added on c3, starting with 1. Lb2 cxb2 2. d6,f6,Ke5 b1=L a.s.o.
- no solution if black pawn is added on d4,f6 or g7
- exactly one solution if black pawn is added on e5

So the "C+" can be added again, I think ... (2021-01-03)
comment
Keywords: Add pieces (b)
Genre: Retro
FEN: 7k/8/4P3/3P1P2/rbP1K1P1/3P1P2/4P3/B7
Input: A.Buchanan, 2021-01-01
Last update: A.Buchanan, 2021-01-03 more...
14 - P1384934
James Malcom
PDB Website 04/01/2020
P1384934
(5+8) C+
h#2
1. b1=B! Lxa3 2. c1=B! Dxc3#
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Keywords: Dummy Pawn, Golden Age (Dummy Pawn), konsekutive Umwandlungen 2 (bb)
Genre: h#
Computer test: Popeye 4.79
FEN: 8/8/8/8/p2Q4/r1pKP3/ppp1P3/k1Bb4
Input: James Malcom, 2021-01-04
Last update: A.Buchanan, 2023-08-04 more...
15 - P1386489
Aurel M. Karpati
Adrian Storisteanu
Yuri Bilokin
Hans-Jürgen Manthey
Viktoras Paliulionis
Andrew Buchanan

PDB Website 15/02/2021
AK, correction AS, YB, HJM, VP & AB
P1386489
(7+4) C+
h#5
1. b2xa1=S Sc4 2. Sxb3 Se3 3. Sd4 Lc4 4. Sdf3 Lf1 5. Sg1 Lg2#
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corrects and simplifies P0552475
A.Buchanan: Please forgive me but I think “under-promotion” is only meaningful for directmates and studies. That’s why I had put in promotion as a keyword, not under-promotion. In helpmates, promotions need to be distinguished of course, and we can put in the officer type in the parameter slot. Under-promotion would still need such a parameter because it’s inexact itself: the worst of all worlds. Even for directmates and studies of course some people consider knight promotion not to be an under-promotion at all, but I wouldn’t go that far myself. There are far too many keywords covering promotion, and at some time we should clean them up, but in the mean time I am open to considering another opinion if it is explained to me. Thank you. (2021-02-15)
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Keywords: Promotion (s), Schlüssel = Eckzug, Promotion key (s), Corner mate, Selfblock, Model mate, Entblockung
Genre: h#
Computer test: Popeye v4.85
FEN: 8/8/1N6/3P4/8/1Pp5/BpP4n/NK5k
Input: A.Buchanan, 2021-02-15
Last update: A.Buchanan, 2021-02-18 more...
16 - P1386614
Thomas R. Dawson
Lion Xray
Andrew Buchanan

PDB Website 19/02/2021
TRD, version LX & AB
P1386614
(13+9) C+
#2
1. hxg6ep+ Lg5 2. Dxg5#
R: 1. g7-g5 Te3-e7+ 2. Kg5-h6+ Lf5-h7+ 3. Kf6-g5 Sd6-e8+
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Black has captured 3 white units. dxcxb accounts for 2. With only one left over, we know that bPh3 never captured. So to explain wPh4, White must have played fxgxh or hxgxh. Combined with dxcxb & exdxcxb, that accounts for all of White's captures.
(a) If White played fxgxh, then the original [wPh] was "waylaid" by an officer, without promoting or capturing.
(b) If White played hxgxh, then the original [wPf] did not capture. We know that [bPf] or [bPg] promoted, using at most one capture.
(b.1) If Black did capture fxg or fxe, then [wPf] did promote to make the balance, and Black's last move can't have been fxg, or the f-file would be blocked to wP.
(b.2) If Black didn't capture fxg or fxe, then [wPf] was waylaid to clear the way for [bPf] to promote.
We don't know which of these three possibilities happened, but in every case:
(1) All captures are accounted for (so e.g. Kg5xSh6 was not possible).
(2) Black did not just play f6xg5.
If Black just played g6-g5, retract prior checking moves and discover retropat as g6 is blocked preventing discovered check by wB now on h7. By elimination, last move was g7-g5 and ep key is ok.
Removes 2 pieces from P1106295, and enriches the retro logic
Henrik Juel: Nice clean-up and careful retro argumentation (2021-02-18)
A.Buchanan: Thanks Henrik - in fact I've just seen that one can uniquely retract a couple of single moves further, see the animation (2021-02-19)
comment
Keywords: En passant as key, Last Moves? (6)
Genre: 2#, Retro
Computer test: HC+ retro musing + Popeye v4.85
FEN: 3KN3/rPp1R2B/pp5k/Q5pP/PPP4b/1p4Pp/1P6/2B5
Input: A.Buchanan, 2021-02-18
Last update: A.Buchanan, 2021-04-16 more...
17 - P1388090
Yuri Bilokin
Andrew Buchanan

PDB Website 03/04/2021
after Martin Gohn
P1388090
(3+7) C+
h#5
1. Kd7 g4 2. Lh1 Lg2 3. Ke6 Lh3 4. Ld5 g5+ 5. f5 gxf6ep#
play all play one stop play next play all
correction of P0505412 with greater economy
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comment
Keywords: Bahnung, En passant as mating move, Model mate
Genre: h#
Computer test: C+, Gustav 4.1d, Brute Force
FEN: B4n2/1bk2pKn/3q4/4p3/8/8/6P1/8
Input: A.Buchanan, 2021-04-03
Last update: A.Buchanan, 2021-11-22 more...
18 - P1389113
Felix Seidemann
Michael Schreckenbach

PDB Website 15/10/2019
FS, corrected MS
P1389113
(3+3) C+
h#2*
* 1. ... Sf3 2. g5 g4#
1. g5 g3 2. gxh4 g4#
play all play one stop play next play all
Corrects P0530949
more ...
comment
Keywords: Tempo Loss (w), Miniature
Genre: h#
Computer test: C+ Popeye 4.61 1... Sf3 2.g5 g4# 1.g5 g3 2.gxh4 g4#
FEN: 8/6p1/7p/5K1k/7N/8/6P1/8
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-28 more...
19 - P1389169
Thomas R. Dawson
Andrew Buchanan

PDB Website 14/10/2019
TRD, correction AB
P1389169
(4+5) C+
h#2
1. d4 Sg6 2. Tg5 Ta6#
play all play one stop play next play all
See P0515072
Henrik Juel: C+ Popeye 4.61
1.d4 Sg6 2.Tg5 Ta6#
pawn asymmetry (2021-05-02)
A.Buchanan: Yes Henrik exactly - every symmetry has to be broken somehow to make the solution unique, and here the point is that the symmetry is just visual, broken by the pawn movement rules (2021-05-02)
comment
Keywords: Symmetrical position, Asymmetrical solution, Model mate
Genre: h#
Computer test: C+ Popeye 4.61
FEN: 5N1K/8/5k1N/1r1p4/4p3/8/4r3/R7
Input: A.Buchanan, 2021-05-02
Last update: A.Buchanan, 2021-05-08 more...
20 - P1389195
Andrew Buchanan
PDB Website 02/05/2021
P1389195
(12+12) C+
#1
PG in 8.0
1. h4 Sf6 2. h5 Se4 3. h6 Sxd2 4. hxg7 Sb3 5. gxf8=S Sxa1 6. Sxh7 Sxc2 7. Dxc2 Txh7 8. Dd1 Th8
play all play one stop play next play all
See P1389196 for the companion.
more ...
comment
Keywords: Unique Proof Game, Homebase (2)
Genre: Retro
Computer test: Popeye v4.85
FEN: rnbqk2r/pppppp2/8/8/8/8/PP2PPP1/1NBQKBNR
Input: A.Buchanan, 2021-05-02
Last update: A.Buchanan, 2021-05-20 more...
21 - P1389196
Andrew Buchanan
PDB Website 2/5/2021
P1389196
(12+11) C+
#1
PG in 8.0
1. c4 b5 2. Db3 bxc4 3. Dxb8 La6 4. Dxa7 Db8 5. Dxa6 Dxb2 6. Dxc4 Dxc1 7. Dxc1 Txa2 8. Dd1 Ta8
play all play one stop play next play all
In full agreement with the organizer of the Discord #1 tourney, someone asked me to post two problems now. They are not entered in the competition, but are registered here in order to avoid later potential anticipation. The author's name will be made public when the Discord results are announced :) Feel free to solve them and comment on them. See P1389195 for the companion.
Henrik Juel: A nice couple of shorties
What is the prize for guessing the author? (2021-05-02)
A.Buchanan: I don't know the prize: I will ask the author when I relay your kind words. Maybe it's a fraction of the prize given for the Discord #1 competition itself? (I.e. glory only.) Apparently a third problem of this set was submitted to the competition (you can probably guess the mate), and the composer was concerned that the publication of that one might cause imaginative folks to construct these other two.
To my mind, this one here is the most interesting of the three.
In any case, all will be revealed very soon. (2021-05-16)
A.Buchanan: Well, bless my soul - look who the author turned out to be :D (2021-05-20)
Henrik Juel: The chess problem community at large may be stunned by this revelation
But not all of us... (2021-05-21)
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comment
Keywords: Homebase (2), Unique Proof Game
Genre: Retro
Computer test: Popeye v4.85
FEN: r3kbnr/2pppppp/8/8/8/8/3PPPPP/RN1QKBNR
Input: A.Buchanan, 2021-05-02
Last update: A.Buchanan, 2021-05-20 more...
22 - P1389458
Lord Dunsany
Andrew Buchanan

PDB Website 11/05/2021
"No more cross-capturing to inconvenience you, Milord."
Lord Dunsany, correction AB
P1389458
(10+9) C+
#3
1. 0-0-0! droht 2. Txb7 droht 3. Tb8#
1. ... Kd8 2. Txa6+ b6,Kc8,Ke8 3. Ta8#
play all play one stop play next play all
Mutex castling
Corrects P1323157.
Henrik Juel: If both White and Black can castle, there is no way to explain sTh7
If only White can castle, both black rooks are original
If only Black can castle, sTh7 is a promoted pawn
So the castlings are mutually exclusive, and the solution
1.0-0-0 thr. 2.Txb7 thr. 3.Tb8# is C+ Popeye 4.61 (2021-05-11)
Henrik Juel: I had a hard time finding the correct Popeye input, which is 'opt cas a1h8'
Good work, Andrew; if you continue like this, you may expect a peerage letter from the british queen, provided Scotland stays in the union... (2021-05-11)
A.Buchanan: Thanks Henrik: yes I can never remember these parameters, but Olive gave me a hint after I got it wrong :) I replaced wSa7 by wLa5 for an extra variation. These problems were just Christmas puzzles for Dunsany every year in the main Literary magazine of the time. So I fix it in that spirit, but I'm sure I've seen other more intricate problems where both sides have one side boxed in by possibly cross-capturing pawns depending on capture-counting (2021-05-11)
Henrik Juel: The additional variation is 1... Kd8 2.Txa6+ b6,Kc8,Ke8 3.Ta8#
Still C+ Popeye 4.61 (2021-05-11)
comment
Keywords: Castling
Genre: 3#, Retro
Computer test: HC+ simple retro thinking + Popeye v4.85
FEN: 4k2r/1p1p1p1r/pRpP1P2/B6p/8/7P/1PP3P1/R3K3
Input: A.Buchanan, 2021-05-11
Last update: A.Buchanan, 2021-07-09 more...
23 - P1389481
Dragomir Rusin
Yuri Bilokin

PDB Website 19/01/2021
DR, correction YB
P1389481
(3+14) C+
h#4
1. ... Txg7 2. Td3 Txg6 3. Sd4 Txg4 4. Sb3 Ta4#
play all play one stop play next play all
Numerous retro tries but none distinct
See P0510541.
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comment
Keywords: No legal last move for White, Check Protection
Genre: h#, Retro
Computer test: HC+ Popeye 4.61 It is obvious that Black made last move, so White begins.
FEN: 4nrRB/2p2pbK/p3p1p1/5n2/3r2q1/5p2/k7/1b6
Input: A.Buchanan, 2021-05-12
Last update: A.Buchanan, 2023-12-07 more...
24 - P1389660
Werner Kuntsche
Andrew Buchanan

PDB Website 14/05/2021
WK, correction AB
P1389660
(10+11) C+
h#2
1. exd3ep g5 2. Lb3 Se6#
play all play one stop play next play all
HJ: Black captured all six missing white men with dxe, exfxgxh, and fxgxh.
So White captured all five missing black men with axb, bxa, cxb/d, and e2xf3xg4, and promoted twice.
Last move was d2-d4, because all other attempts give illegal checks, so the ep key is legitimized.
Corrects P1389486
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comment
Keywords: En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye 4.61 with analysis
FEN: 8/6pp/7b/7P/P1kPpNPR/n1p2B1p/p4PPp/2Kb4
Input: A.Buchanan, 2021-05-16
Last update: A.Buchanan, 2021-05-16 more...
25 - P1394496
Vladimir Archakov
Andrew Buchanan

PDB Website 10/10/2021
VA, correction AB
P1394496
(15+3) C+
#2*
Set Play
1. ... Kxh1 2. Kf2#
1. ... Kxh3 2. Sf4#
1. ... Kxf3 2. Lb7#
BTM
1. ... hxg5 2. Sc3
2. ... Kxh1 3. Kf2#
2. ... Kxh3 3. Lf1#
2. ... Kxf3 3. 0-0#
play all play one stop play next play all
Corrects P0000914.
Black to move.
Missing White unit captured on h-file. So wPa promoted, hence 11 necessary captures by White, within budget.
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comment
Keywords: No legal last move for Black, Mutate (2), Castling (wk)
Genre: 2#, Retro
Computer test: Henrik Juel: C+ Popeye 4.61 (2021-10-10)
FEN: 8/6PR/B6p/6BP/3P2Np/5P1P/3PN1kP/Q3K2R
Input: A.Buchanan, 2021-10-10
Last update: A.Buchanan, 2023-08-15 more...
26 - P1394733
Andrew Buchanan
PDB Website 19/10/2021
to Tivadar "of Thorn" Kardos
P1394733
(13+12) C+
BP in 6,0
1. Sf3 e5 2. Sxe5 Dg5 3. Sc6 Dxd2+ 4. Dxd2 Sf6 5. Dxd7+ Sfxd7 6. Sxb8 Sxb8
play all play one stop play next play all
Suggested by P0000541. If Tivadar's problem had been a double homebase, it would have been the first in the world, pipping by 8 months P0002288, Andrey Frolkin's rendering of E.C.Mortimer.
See also: https://gatherer.wizards.com/pages/card/details.aspx?name=Tivadar%20of%20Thorn
The flavour text suggests the impostor theme: "His blade came down upon the neck of a goblin — but not the one he had charged. When Tivadar looked up, the world he had known was gone."
Since the beginning in 1993, Magic the Gathering has had white and black knights as a kind of homage to chess. These creatures have evolved and Tivadar of Thorn is literally a white knight, who in chess terms we see charging out from g1. There are two main kinds of white knight: the anti-black and the anti-red, and Tivadar is the latter.
YM: Sorry - two impostors were in P1329742 (2021-10-20)
A.Buchanan: Is there a mode for viewing PDB problems where one doesn't get to see the keywords (or the solution, which also a bit of a hint)? (2021-10-20)
A.Buchanan: Yes, YM, your P1329742 is very good. And single impostor in homebase:2 is demonstrated in PG in 4.0. I wanted to post this one because I was surprised to render the problem sound just by j'adoubing one unit to its home square! There's also an interesting artistic cross-over with Magic the Gathering. (2021-10-21)
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comment
Keywords: Unique Proof Game, Homebase (2), Impostor (s), Quasi-symmetrical position
Genre: Retro
Computer test: C+ Euclide 1.01
FEN: rnb1kb1r/ppp2ppp/8/8/8/8/PPP1PPPP/RNB1KB1R
Input: A.Buchanan, 2021-10-20
Last update: A.Buchanan, 2021-10-24 more...
27 - P1395170
Jozsef Frankl
Ladislav Packa

PDB Website 17/08/2011
JF, correction LP
P1395170
(8+9) C+
h#3*
*) 1. ... 0-0-0 2. Kd7 Tf1 3. Se8 Tf7#
1) 1. 0-0 a4 2. Kh8 Ta3 3. Tg8 Th3#
play all play one stop play next play all
Corrects P0534301 & P0003629
Ladislav Packa: Maybe -wPd2, -wPh2, + bPe3, + bPg4 would be better. The difference between 0-0-0 and Rd1 would show. (2022-04-16)
comment
Keywords: Homebase
Computer test: HC+ Popeye v4.8 + trivial retro-logic
FEN: 2brk2r/2n3p1/2ppp3/8/8/8/PPPPP2P/R3K3
Input: A.Buchanan, 2021-10-31
Last update: A.Buchanan, 2021-10-31 more...
28 - P1396159
Tivadar Kardos
James Malcom
Andrew Buchanan

PDB Website 24/11/2021
TK, correction JM & AB
P1396159
(6+15) C+
h#3
1. dxe3ep+ Kxc4 2. Lc3 Sxc2 3. Ta5 axb3#
R: 1. e2-e4 Tf3-d3+ 2. Ke4-d5
play all play one stop play next play all
See P0003211

Example Proof Game: 1. b3 a5 2. c4 a4 3. Na3 b5 4. d4 c5 5. Bg5 h6 6. f4 hxg5 7. Nf3 gxf4 8. Qd3 bxc4 9. Nc2 axb3 10. Rc1 Bb7 11. Na1 Nf6 12. Rc3 Nh5 13. Qe3 fxe3 14. Nd2 exd2+ 15. Kf2 Nf4 16. Rg1 Nh3+ 17. gxh3 Bh1 18. Rcg3 Ra6 19. Rg6 Rf6+ 20. Ke3 Rh5 21. Bg2 Nc6 22. Be4 Na5 23. Bc2 bxc2 24. R1g4 Rf3+ 25. Ke4 Nb3 26. Rd6 exd6 27. Rf4 Qh4 28. Rg4 Qe1 29. Rf4 Kd8 30. Rg4 Kc7 31. Rf4 Kb6 32. Rg4 Ka5 33. Rf4 Ka4 34. Rg4 Rhf5 35. Rh4 g5 36. Rg4 Bg7 37. Rh4 Be5 38. Rf4 cxd4 39. Rg4 f6 40. Rh4 Qf1 41. Rf4 gxf4 42. Kd5 Rd3+ 43. e4
Henrik Juel: Black pawns captured all 10 missing white men, and White captured g2xSh3
Last move was not e3-e4 (because of the check from Lh1), but e2-e4
HC+ Popeye 4.61 (2021-11-24)
A.Buchanan: I’d like to claim that Popeye + Retractor + example proof game means this problem is C+. If not, what more would be required. (2021-11-24)
Henrik Juel: I guess that suffices (2021-11-24)
comment
Keywords: En passant as key, Checking key
Genre: h#, Retro
Computer test: C+ Popeye 4.61 for forward play Retractor 2.0 for retraction Lichess to check demo game
FEN: 8/3p4/3p1p2/3Kbr2/k1ppPp2/1n1r3P/P1pp3P/N4q1b
Input: James Malcom, 2021-11-24
Last update: A.Buchanan, 2023-07-13 more...
29 - P1396163
Tivadar Kardos
Andrew Buchanan

PDB Website 24/11/2021
TK, correction AB
P1396163
(8+14) C+
h#3
1. cxb3ep+ Sb4+ 2. Kb1 Sxe2 3. b2 0-0#
R: 1. b2-b4 Tc3-a3+ 2. Sa3-c2
play all play one stop play next play all
Black captured 8 white men with pawns. Critically sBd & sBe never captured, therefore White pawns captured onto d- & e-files (to explain the pawn inversions there). Therefore wBb4 did not come from c3.
See P0574383.

With the ink still wet on this correction, I would like to remove sD. Sound by Popeye & Retractor, but needs an adapted proof game for C+.

Proof Game: 1. c4 a6 2. g3 Nc6 3. Bg2 Na5 4. Bc6 h5 5. Bb5 axb5 6. g4 c5 7. d4 cxd4 8. e4 f5 9. Be3 fxe4 10. f4 g5 11. Qf3 Nb3 12. Na3 hxg4 13. Nc2 gxf3 14. Rd1 Na1 15. Rd2 Ra3 16. Rg2 Rc3 17. a4 d3 18. Bf2 e3 19. Bg3 e5 20. Re2 e4 21. a5 d5 22. a6 d4 23. a7 Qd5 24. a8=R Qe5 25. Rf2 Kd7 26. Re2 Nf6 27. Rd2 Nd5 28. cxd5 Kd6 29. Rf2 Kc5 30. Re2 b6 31. Rd2 Kc4 32. fxe5 Kb3 33. Re2 fxe2 34. Rb8 Bg4 35. Rb7 Bf3 36. Rc7 Ka2 37. Bf4 gxf4 38. Rc6 Bb4 39. Rc5 Rh3 40. Na3 Ba5 41. Rc4 bxc4 42. Nc2 Ra3+ 43. b4
A.Buchanan: 6n1/8/1q6/b7/1Ppppp2/r2ppp1r/k1N1p2P/n3K1NR has one less piece again, but I prefer the current version as retro logic is more interesting. (2021-11-26)
James Malcom: Enjoy an optimal PG Andrew. The total sum of the queen & knight journeys is 8 no matter which knight ends up on a1. (2021-11-27)
A.Buchanan: :-) thanks James (2021-11-27)
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comment
Keywords: En passant as key, Castling (wk)
Genre: h#, Retro
Computer test: C+ Popeye 4.61, Retractor 2.0 & example proof game.
FEN: 8/8/1p6/b2PP3/1Ppppp2/r2ppb1r/k1N1p2P/n3K1NR
Input: A.Buchanan, 2021-11-24
Last update: A.Buchanan, 2023-08-15 more...
30 - P1396199
Tivadar Kardos
Andrew Buchanan

PDB Website 25/11/2021
TK, version AB
P1396199
(10+13) C+
PG in 8.5
1. Sc3 Sf6 2. Se4 Sxe4 3. g3 Sxg3 4. Sf3 Sxh1 5. Se5 Sxf2 6. Sxd7 Sxd1 7. Sxb8 Txb8 8. Kxd1 Ta8 9. Ke1
play all play one stop play next play all
P0000736 plus the 1.5 obvious moves. Why did he stop? :-)
Henrik Juel: He probably stopped because
1. he was afraid of cooks
2. the Homebase theme was unknown in 1979
Is the extension to 8.5 C+? (2021-11-25)
Olaf Jenkner: This version is in my opinion 100 times better than P0000736, a homebase with 9 missing men in only 8.5 moves.
Is there a record list of proof games "homebase with x missung men" in a minimum number of moves? (2021-11-25)
A.Buchanan: Thanks Olaf for your kind words. I don't think there is such a list. PDB has today 19 homebase unique PGs which are no longer than this with no fewer captures. Most are 9 captures but P1000453 by Le Gleuher alone manages to get a 10th capture. He also manages the shortest (6.5 moves P1000944), with 7.5 moves by Mintz P1329742 as runner-up, and 4 others in 8.0. To be fair, the aesthetic for the Future Proof Game gang has generally been to *minimize* the number of captures. Except for Mintz and one other, all involve promotions. (2021-11-26)
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comment
Keywords: Unique Proof Game, Homebase (2), Switchback (Kt)
Genre: Retro
Computer test: C+ Natch 3.1 in 53 minutes
FEN: r1bqkb1r/ppp1pppp/8/8/8/8/PPPPP2P/R1B1KB2
Input: A.Buchanan, 2021-11-25
Last update: A.Buchanan, 2021-11-26 more...
31 - P1396304
Tivadar Kardos
Andrew Buchanan

PDB Website 27/11/2021
Happy Birthday to James Malcom!
A gift from Tivadar Kardos (helped a little by Andrew Buchanan)
I don't think this one needs a proof game :)
TK, version AB
P1396304
(11+13) C+
h#3
2 solutions
1. Lxa2 Txa2 2. 0-0-0 Txa7 3. Td7 Ta8#
1. Dg3 Txb1 2. Dxb3 Txb3 3. 0-0 Tg3#
1. Lxa2 0-0-0? 2. Dxg2 Tg1 3. 0-0 Txg2# (White can't castle)
play all play one stop play next play all
The cooked P0006972 can be fixed many ways. I wanted to find a single touch that would keep the intended solution, the intended try, and exactly one of the cooks which seemed worth saving, while eliminating all the other cooks.
Henrik Juel: Black captured [Lf1] and the remaining 4 missing white men with exdxcxTb2-b1=L and gxh
1.Bb1*a2 Ra1*a2 2.0-0-0 Ra2*a7 3.Rd8-d7 Ra7-a8 #
1.Qg8-g3 Ra1*b1 2.Qg3*b3 Rb1*b3 3.0-0 Rb3-g3 #
Not 1.Bb1*a2 0-0-0? 2.Qg8*g2 Rd1-g1 3.0-0 Rg1*g2 # (White may not castle, as he has moved his king)
Neat birthday greeting (2021-11-27)
James Malcom: Thanks for the warm gift Andrew. Huzzah! (2021-11-28)
comment
Keywords: Castling (sgsk), Cant Castler (wg), Obvious promotion (l)
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 + trivial retro-logic
FEN: r3k1qr/pp3p1p/1bp5/3pB2p/8/1P6/P1PPPPPP/Rb2K3
Input: A.Buchanan, 2021-11-27
Last update: A.Buchanan, 2021-11-28 more...
32 - P1397613
Tivadar Kardos
Andrew Buchanan

PDB Website 31/12/2021
TK, correction AB
P1397613
(6+4) C+
hs#4
1. d4 Td2 2. Lc3 Lc1 3. d5+ e5+ 4. dxe6ep+ Td4#
play all play one stop play next play all
Fixes cook in P1303210, and improves economy & precision
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comment
Keywords: En passant
Genre: Fairies
Computer test: C+, Gustav 4.2a, Brute Force
FEN: 4R3/4p3/5k2/8/5K2/b4PR1/1r1P4/B7
Input: A.Buchanan, 2021-12-31
Last update: James Malcom, 2022-01-02 more...
33 - P1398014
Tivadar Kardos
Andrew Buchanan

PDB Website 08/01/2022
TK, correction AB
P1398014
(6+16) C+
h#3
1. bxc3ep+ d3 2. 0-0 Tf4 3. Kh8 Txf8#
play all play one stop play next play all
Not R: 1. c3-c4? La6xb5? because Black's 10 captures are already accounted for: 6 pawn captures on files a-d, e.g.: bax, cxbxa, dxcxbxa + 4 waylaid pawns on files e-h or maybe 2 more pawn captures if bPe & bPf cross-capture.
Corrected version of P0003264, with extra tightness.
more ...
comment
Keywords: En passant as key, Castling (sk)
Genre: h#, Retro
Computer test: HC+ Popeye 4.61
FEN: N3k2r/6pp/1pn5/Pb2p3/RpP5/pr2qp2/p2P2n1/5Kb1
Input: A.Buchanan, 2022-01-07
Last update: A.Buchanan, 2022-03-20 more...
34 - P1398474
James Malcom
PDB Website 16/1/2022
P1398474
(5+3) C+
h#2
1. g1=B Lf3 2. f1=B Td2#
play all play one stop play next play all
Better economy than P1384934
SCHRECKE: Die Idee ist als Miniatur darstellbar!
W: Kh4,Ta1,Ld1,Sg1 (4) - S: Kh2,Be2,Bf2 (3)
Lösung: 1.e1B Lf3 2.f:g1B Ta2# (2022-01-25)
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comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn)
Genre: h#
Computer test: C+, popeye 4.87, bedingung UWnur D T L S B
FEN: 8/8/8/8/3RP2K/4P3/5ppk/7B
Input: James Malcom, 2022-01-16
Last update: A.Buchanan, 2023-08-04 more...
35 - P1398644
Andrew Buchanan
PDB Website 26/01/2022
to James Malcom
P1398644
(4+8) C+
h#3 (-:
1. e1=B Lf3 2. d1=B Le3 3. f1=B Tb2#
play all play one stop play next play all
AB: economy record for 3 Dummy Pawns in h#. Meredith. Black moves open 6 lines, White moves close 3 lines.
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comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn)
Genre: h#
Computer test: C+ Popeye 4.79
FEN: 8/8/1Rb1qr2/8/7K/8/3ppp1k/r1BB4
Input: A.Buchanan, 2022-01-26
Last update: A.Buchanan, 2023-08-04 more...
36 - P1398666
James Malcom
Michael Schreckenbach
Andrew Buchanan

PDB Website 26/01/2022
P1398666
(4+3) C+
h#2 (-:
1. g1=B Lf3 2. e1=B Te2#
play all play one stop play next play all
AB: economy record for 2 Dummy Pawns in h#. Miniature. Aimless promotion.
Henrik Juel: wPg3 prevents cooks like 1.Kg1 Kg3 2.e1=DTLSB Txe1# (2022-01-27)
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comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn), Miniature, Tempo Move (Promotion)
Genre: h#
Computer test: C+ Popeye 4.79
FEN: 8/8/8/8/4R2K/6P1/4p1pk/7B
Input: A.Buchanan, 2022-01-27
Last update: A.Buchanan, 2023-08-04 more...
37 - P1398987
Ado Kraemer
Andrew Buchanan

PDB Website 10/02/2022
AK, correction AB
P1398987
(2+8)
#3
(-:
hint rot13.com:qrynl pubvpr bs cebzbgrq havg
1. "b8..."
1. ... g2 "...=S!" 2. Sd7 g3 3. Sf6#
1. ... h2 "...=D!" 2. Df8 Th3 3. Dxh6#
play all play one stop play next play all
If White were prescient, they could choose which unit to promote to, based on knowledge of Black's next move. As it is, White plays 1.b8, then only chooses the promotion officer when Black's response is known.
Supersedes the dualized and inexact P1373527
White waits for Black to move before selecting the promoted unit.
Under this joke, a dummy pawn exists ephemerally, but not via the Dummy Pawn rule.
Position comfortably legal.
Henrik Juel: Andrew, how does one decode the rot13 hint? (2022-02-10)
Henrik Juel: Never mind, Andrew; write the english alphabet in two rows and code/decode between rows
abcdefghijklm
nopqrstuvwxyz
so the gobbledygook translates to
delay choice of promoted unit (2022-02-10)
Henrik Juel: ... the rows should be written with a fixed font, of course, but I do not know how to accomplish this in a PDB comment (2022-02-10)
A.Buchanan: Hi Henrik: got to rot13.com and put the text in the input box, read it from the output box. Because 13=26/2, this works for both encryption and decryption.
Trying to do this for new jokes to create a level playing field. If you want a hint as to the silly trick, but would still enjoy solving the chess afterwards, then check out the rot13. (2022-02-10)
A.Buchanan: The real challenge is getting animation to work properly in this site. (2022-02-10)
more ...
comment
Keywords: Joke (delayed promotion), Minimal, Dummy Pawn (not! Delayed promo)
Genre: Fairies
FEN: 8/1P5K/6pp/6pk/6pr/6pp/8/8
Input: A.Buchanan, 2022-02-10
Last update: A.Buchanan, 2023-05-21 more...
38 - P1399112
Werner Kuntsche
Valery Liskovets
Andrew Buchanan

PDB Website 14/02/2022
WK, correction AB
P1399112
(5+8) C+
h#3 AP

No solutions except for those beginning with e.p.
297 candidate solutions begin 1.gxf3ep, but only one includes castling. Queenside 2. ... 0-0-0
22 candidate solutions begin 1.fcxd3ep, but only one includes castling. Kingside 2. ... 0-0
In some way, these are trying to be combined so that from AP perspective, White's last move can only have been double hop with wBd or wBf.
We need a clear delineation of the precise PRA-AP algorithm to be followed.

The point: if this problem is "sound", then surely P1382808 is "unsound", because there only one of the two parts needs to prove that White castling rights remain, so there are 4 cooks.
This is an important schema for AP. Previous cooked problems P0002476 & P0004295 (together with versions of each lacking sBe3) had multiple chess cooks that do not involve e.p. as key. This chessically sound composition allows us to focus on the fundamental theoretical issue of AP.

The double e.p. idea cannot work as an AP retro strategy problem, because one can never prove that one double pawn hop rather than the other occurred. PRA+AP seems potentially feasible, but I see no clear statement of how the normal PRA method should be extended to this case. All prescriptive suggestions are welcome.

In WinChloe, I found a correction from 2002 by Valery Liskovitz, just posted in PDB as P1401449. However it used three extra pawns, rather than 2, so the current version still has merit, but I will add Valery as co-corrector.

See also P1399178.
more ...
comment
Keywords: a posteriori (AP) (Type Petrovic), En passant as key (2), Symmetrical position, Symmetrical solution, Castling (wb)
Genre: h#, Retro
Computer test: HC+ Forward play proved by Popeye v4.87 AP logic requires some framework but I think we know we want this cool idea to end up being sound.
FEN: 8/8/2p3p1/8/2pPkPp1/2n1p1n1/8/R3K2R
Input: A.Buchanan, 2022-02-14
Last update: A.Buchanan, 2022-05-24 more...
39 - P1400191
James Malcom
Andrew Buchanan

PDB Website 02/04/2022
P1400191
(8+7) C+
r#4
1. bxa8=B! f1=B 2. e8=B d1=B 3. Le1 Sc2 4. Lb1 Te3#
play all play one stop play next play all
More economical version of P1375039
James Malcom: I had a thought looking at this again. Does n7/1P2P3/Q3P3/1r6/N1k1KP2/Pr6/B2p1p2/n7 work to save another piece? (2022-04-02)
A.Buchanan: James, yes your version does save another unit for your lovely idea. Beyond this, a version n7/1P2P3/Q7/Br6/2kPKP2/1r6/B2p1p2/n7 saves another unit, and forces a unique order on the Black promotions too. To avoid distracting unachievable threats, set NoThreat as well as the usual NoShortVariations. Your composition has driven me finally to report a long-standing Olive bug that cruelly punishes we Dummy Pawn enthusiasts: https://github.com/dturevski/olive-gui/issues/54. (2022-04-03)
James Malcom: Thanks for the verification and shaving off a unit, Andrew. (2022-04-03)
more ...
comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn), Superseded by (P1411297)
Genre: Fairies, r#
Computer test: Henrik Juel: C+ Popeye 4.87 (2022-04-02)
FEN: n7/1P2P3/Q7/Br6/2kPKP2/1r6/B2p1p2/n7
Input: James Malcom, 2022-04-02
Last update: A.Buchanan, 2023-12-14 more...
40 - P1401525
Joao Baptista Santiago
Andrew Buchanan

PDB Website 30/05/2022
JBS, correction AB
P1401525
(11+14) C+
h#2* (AP)
1. ... Kd2 2. e3+ fxe3#
1. bxc3ep b3 2. Kxd3 0-0-0#
play all play one stop play next play all
Black has no tempo moves to convert the set play to a main play solution. Rc5~,Se5~,e3,Sf1 all disrupt the set play.
The main play castling is needed both for the mate and for the legitimization.
Corrects P1401496
Henrik Juel: analysis
Black captured [Pa2] with an officer and cxb, dxe, exf, and f3xg2
White captured g4xLh5 and h2xDg3, so if he may castle, Black may capture ep now (2022-05-30)
A.Buchanan: A detail I hadn't noticed: bPh never captured, so wPh5 must have arrived on h-file *above* the light square h3. If it was gxh4, then there was no light square to capture light bB, so it was gxh5. But the capture might have been h3xBg4xQh5. The problem is still sound: the last move can't have been h4-h5. (2022-05-30)
more ...
comment
Keywords: a posteriori (AP) (Type Petrovic), Castling (wg), En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye 4.61 and analysis
FEN: 8/8/pp2P3/brr1n2P/1pPkp1p1/B2P1pPp/1P3Ppn/R3K1N1
Input: A.Buchanan, 2022-05-30
Last update: A.Buchanan, 2022-05-30 more...
41 - P1401526
Zoltan Laborczi
Gabor Tar
Andrew Buchanan

PDB Website 30/05/2022
ZL & GT, version AB
P1401526
(4+8) C+
h#2 (AP)
3.1...
1. Tb3 Lxc4 2. Txb4 Txa2#
1. Kxb4 Tb1+ 2. Ka4 Lb5#
1. cxb3ep 0-0-0! (Td1?) 2. e4 Td4#
play all play one stop play next play all
Economizes P1080354 by 2 units, adding a solution.
more ...
comment
Keywords: a posteriori (AP) (Type Petrovic), Castling (wg), En passant as key
Genre: h#, Retro
Computer test: C+ Popeye 4.61
FEN: 8/1p6/B7/p3p3/kPp5/r1p5/p7/R3K3
Input: A.Buchanan, 2022-05-30
Last update: A.Buchanan, 2023-05-21 more...
42 - P1402593
Andrew Buchanan
PDB Website 09/07/2022
after G.P.Latzel
P1402593
(10+4)
h#1.75 (-:
hint rot13: pbqrk negvpyr svsgrra
0. ... [-bPg5] 1. Lxb3 Ta8#
play all play one stop play next play all
Clearly an unfinished move joke. By a usual convention for these things, a player might be halfway through a castling, an en passant, or a promotion. 1.75 is nearly 2.0, so Black would be the moving player.

Black is not in the middle of an e.p. or castling, so the only possibility is a promotion. Black has lifted up the pawn, to replace it with an officer on the 8th rank. However, White has apparently made 12 pawn captures, accounting for all missing Black units, so Black is not part way through promoting a pawn.

Therefore it's not Black in the middle of a move. By a joke application of Article 15, we say that it's *White* in the middle of a move instead. So 1.75 - 0.5 = 1.25 and it's h#1.25.

- White can't be part way through a promotion, because all White pawns are on the board.
- If White were in the middle of castling, then the pawn capture balance would be ok, but Black would have no prior move.
- If White were in the middle of en passant h5xg6, then bPg5 can help with capture balance, but still there is one capture short for the balance.
- So White is in the middle of en passant f5xg6. If we complete the joke move by removing bPg5, then the position is legal, with 12 White pawn captures and 13 missing Black units. A sound h#1 awaits.
After P0004346
Henrik Juel: Not completion of 0-0-0, because Black has no last move
Completion of f5xg6ep is feasible, and then 1.Lxb3 Ta8#
Stipulation should be h#1.25, I think (2022-07-10)
A.Buchanan: Hi Henrik: it’s intended to be h#1.75 :-) Can black complete any Valladao move? And if not then what do we do? :-) (2022-07-10)
Henrik Juel: Thanks Andrew
So Black must complete a move, but his four men are stuck, and white pawns captured the remaining 12 black men; so there is nothing for Black to complete
Looks like a weird joke... (2022-07-10)
A.Buchanan: Sorry you don't like the Valladao joke Henrik. "1.75 minus 0.5 = 1.25" is a novel way to combine "unfinished move" with Article 15. I also like the fact that all the cases of pawn capture counting are exact, with no "retro dressing" unit purely to contribute to a balance.s (2022-07-10)
comment
Keywords: Joke, Complete an unfinished move, En passant, Castling (wg Not!), Promotion (Not!), No legal last move for Black
Genre: h#, Retro
FEN: 7k/5p1P/5PPP/1P4p1/b7/1P6/6PP/R1K5
Input: A.Buchanan, 2022-07-10
Last update: A.Buchanan, 2023-12-08 more...
43 - P1404422
Mikhail Mikhaylov
Henrik Juel
Mario Richter
Andrew Buchanan

PDB Website 17/09/2022
MM, correction HJ, MR & AB
P1404422
(7+6) C+
#2v (-:
1. d8=sL? droht 2. g8=S#
1. ... Lc7 2. Sd7#
1. ... Lb6 2. Te6#
but 1. ... La5!

1. d8=sS! droht 2. g8=S#
1. ... Sb7 2. Sd7#
1. ... Sc6 2. Te6#
1. ... Se6 2. Se4#
1. ... Sf7 2. Sg4#
play all play one stop play next play all
Henrik Juel: Try 1.d8=sL? thr. 2.g8=S#, 1... Lc7/Lb6 2.Sd7/Te6#, but 1... La5!
Solution 1.d8=sS thr. 2.g8=S#, 1... Sa7/Sc6/Se6/Sf7 2.Sd7/Te6/Se4/Sg4#
Thanks for your efforts, Andrew (2022-09-18)
comment
Keywords: Joke, Joke promotion (sl)
Genre: 2#
Computer test: C+ Popeye v4.87, using PostKeyPlay option to simulate promotion to foreign officers
FEN: r7/q2Pp1P1/r4k1N/2N3R1/5p1K/8/8/4R3
Input: A.Buchanan, 2022-09-18
Last update: A.Buchanan, 2023-05-21 more...
44 - P1410177
James Malcom
PDB Website 6/6/2023
P1410177
(13+6)
s#5
(-:
1. cxd8=B+ Kd6 2. e8=B+ Ke6 3. Lc4+ Kxf6 4. Le7+ Kxg6 5. g8=B Txh3#
play all play one stop play next play all
Improvement in move number and economy over P1379580.
SCHRECKE: Here is a s#7 with 4 dummy pawns: QnRn1B1K/P1P1P1P1/k1N5/3p2p1/2PPB1P1/8/4p1pR/4Nbrr
1. axb8=B+! Kb6 2. Da7+ Kxc6 3. cxd8=B+ Kd6 4. e8=B+ Ke6 5. Lxd5+ Kf6 6. Le7+ Kg6 7. g8=B Txh2#
Who makes it better? (2023-06-07)
James Malcom: Wonderfully done. I had an illegal scheme for four I never realized, but now it is done: 1RrRq1BK/pP1P1PP1/Pk2N1N1/p3p1p1/p2PP1P1/3Q3p/6pr/6Bb

I see no improvements to yours, yet. (2023-06-07)
comment
Keywords: Dummy Pawn (x3), Golden Age (Dummy Pawn), Construction record
Genre: s#
Computer test: Popeye 4.69
FEN: 2Rn1B1K/2P1P1P1/P1k2NN1/6p1/6P1/7R/6pr/5BQb
Input: James Malcom, 2023-06-06
Last update: A.Buchanan, 2023-08-04 more...
45 - P1410859
Michael Schreckenbach
James Malcom

PDB Website 07/06/2023
P1410859
(15+10)
s#7
1. axb8=B+! Kb6 2. Da7+ Kxc6 3. cxd8=B+ Kd6 4. e8=B+ Ke6 5. Lxd5+ Kf6 6. Le7+ Kg6 7. g8=B Txh2#
play all play one stop play next play all
Commented on P1410177
SCHRECKE: Dear James, the authors should be Malcolm/Schreckenbach. (2023-07-11)
James Malcom: Done. (2023-07-12)
comment
Keywords: Dummy Pawn (x4), Construction record
Genre: s#
Computer test: Popeye 4.69
FEN: QnRn1B1K/P1P1P1P1/k1N5/3p2p1/2PPB1P1/8/4p1pR/4Nbrr
Input: James Malcom, 2023-07-11
Last update: James Malcom, 2023-07-12 more...
46 - P1411367
Michael Schreckenbach
PDB Website 28/07/2023
P1411367
(9+7)
S#2 (-:
SCHRECKE: C+, popeye 4.87
1. f7! (Zugzwang)
1. ... Txa8 2. bxa8
1. ... Tb8 2. cxb8
1. ... Tc8 2. bxc8
1. ... Td8 2. cxd8
1. ... Te8 2. fxe8
1. ... Tg8 2. fxg8 (2023-07-29)
SCHRECKE: Hi Andrew, thanks for the diagram. (2023-07-29)
comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn)
Genre: s#
FEN: R4r1k/pPP3R1/rp3PKn/p5PQ/P7/8/8/8
Input: A.Buchanan, 2023-07-29
Last update: A.Buchanan, 2023-07-29 more...
47 - P1413924
Johannes Jacob Burbach
Alain C. White
Andrew Buchanan

PDB Website 05/12/2023
JJB & ACW, version AB
P1413924
(4+6) C+
h#2
b) -sBg6h7
a) 1. Ta5 Kd1 2. Ta2 Kc2# (not 1.Ta7?etc Lxc3 because White may not castle)
b) 1. Ta7 Lxc3 2. Ta2 0-0# (last move could be 0.h7-h8=L)
play all play one stop play next play all
See P0003666
A.Buchanan: Apart from having removed wBe2/sBe3, I don't think this is an improvement. In the original, sBh6 gave and took. The version is more economical but there's two pawns difference between the twins. (2023-12-06)
more ...
comment
Keywords: Cant Castler, Castling (wk), Remove pieces
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 + trivial retro logic
FEN: 7B/6rp/6p1/7r/8/2p5/1P6/k3K2R
Input: A.Buchanan, 2023-12-05
Last update: A.Buchanan, 2023-12-05 more...
48 - P1413983
Marcin Banaszek
PDB Website 08/12/2023
nach I.Nemes 1994
P1413983
(12+6) C+
s#7
1. b7-b8=T+! Kb5-c6 2. c7-c8=T+ Kc6-d6 3. d7-d8=T+ Kd6xe6 4. e7-e8=T+ Ke6xf6 5. f7-f8=T+ Kf6-g6 6. g7-g8=T+ Kg6-h6 7. h7-h8=T+ Lc2-h7#
play all play one stop play next play all
SCHRECKE: Nemes: P1302865 (2023-12-08)
comment
Keywords: konsekutive Umwandlungen 7 (TTTTTTT)
Genre: s#
Computer test: Gustav 4.1c
FEN: 8/RPPPPPPP/4BB2/1kp3q1/2r3P1/8/2br4/2K5
Input: Marcin Banaszek, 2023-12-08
Last update: Marcin Banaszek, 2023-12-08 more...
49 - P1415606
Maurice Jago
Andrew Buchanan

PDB Website 07/03/2024
MJ, correction AB
corrects 8202v Die Schwalbe, p.148, 10/1980
P1415606
(8+15)
h#2
b) sBb4->b5
Supersedes P0003659.
"The noted Cornish problemist, Dr. Maurice Jago was most prolific during the war when he was a lieutenant in the Royal Army Medical Corps. He became increasingly interested in the more flamboyant and unusual kinds of positions and problems." (www.keverellchess.com, now closed)
Yuri Bilokin: perhaps such a version does not harm the author's intention –wNa7, -wNa8, -wBb8, -wPd3, -bRc8, -bPc7, -bPe7 8/8/1Pqp4/2bb4/1p6/n1p2rP1/1PP1P2k/R3KQ1n (8+12) h#2 b) bPb4-b5 (2024-03-10)
Yuri Bilokin: slip of the pen -wNa7, -wNa8, -wBb8, -wPd3, -bRc8, -bPc7, -bPe7, -bPa4, -bPg6 8/8/1Pqp4/2bb4/1p6/n1p2rP1/1PP1P2k/R3KQ1n (8+10) h#2 b) bPb4-b5 (2024-03-10)
A.Buchanan: Hi Yuri thanks yes it’s more than intention here. In b need to ensure that White can’t have just played axb6, fxg3 or g2-g3, in order to eliminate the castling try: the extra pieces are all to ensure this (2024-03-11)
Yuri Bilokin: Hi Andrew. I apologize, I didn't go there, although the white horse on the a8 square still bothers me. (2024-03-11)
A.Buchanan: WP cap: axb BP caps: fxexdxc. bPh must have promoted, so either bPh3xg2-g1= or wPh was waylaid. In any case, all captures are accounted for. wPf promoted. Easy to see that White cannot have just played g2-g3 or f2xg3 or d2-d3 or axb6. So must have bPb4 rather than b5, allowing for White to have just played Sb5-a7 or b5-b6. If any of the "retro-dressing" White pieces e.g. Sa8 are removed, then White might have just played g2-g3 or d2-d3. At least the retro-dressing units have no possible last move (& wSa8 wBb8 have not just promoted), so there is some craft to their deployment. (2024-03-11)
A.Buchanan: bPg6 blocks a cook so must stay there, but can shift bPe7 to d7 (allowing the removal of wSa8 or wBb8) or to b3/b7 (allowing the removal of all three White officers: wSa7a8 & wBb8.) Maybe that's worth doing? (2024-03-11)
Yuri Bilokin: Thank you for the detailed analysis. Perhaps my poor view will allow you to get an optimal starting position. (2024-03-11)
Henrik Juel: a) 1.Sh1-f2 Qf1*f2 + 2.Kh2-h1 0-0-0 #
b 1.Sa3-b1 Ra1*a4 2.Sh1*g3 Ra4-h4 # (2024-03-11)
Henrik Juel: C+ Popeye 4.61 and analysis (2024-03-11)
A.Buchanan: I had wanted to keep to the spirit of P0003659, in which may be the author wanted to have a bunch of White retro-dressing that could not retract. But going back to the first version P0003659, the White position is much cleaner. So following Yuri being bothered by a horse, I am going to change the diagram here from NBr5/N1p1p3/1Pqp2p1/2bb4/pp6/n1pP1rP1/1PP1P2k/R3KQ1n by removing 4 white units. Hope this is agreeable to all (2024-03-13)
more ...
comment
Keywords: Cant Castler, Castling (wg)
Genre: h#, Retro
FEN: 8/rpp2p2/1Pqp4/2bb4/pp6/n1p2rP1/1PP1P2k/R3KQ1n
Input: A.Buchanan, 2024-03-06
Last update: A.Buchanan, 2024-03-13 more...
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The problems of this query have been registered by the following contributors:

Marcin Banaszek (2)
A.Buchanan (36)
James Malcom (11)