Die Schwalbe

14 problem(s) found in 3141 milliseconds (displaying 14 problem(s)). [COMMENTDATE>=20200919 AND NOT K='Hilfsrückzüger' AND K='En passant als Schlüssel']

1 - P0000793
Nikita M. Plaksin
Andrey Lobusov

1558 Die Schwalbe 33 06/1975
4. Preis
(13+5) C+
#3 (AP)
1. cxd6ep+! Kxg3 2. 0-0! (proving ep ok)
2. ... Kg4 3. g8=D,T#
2. ... a1=D,L 3. Dg5#

R: 1. d7-d5 Tc6xh6 (unless R: Kg1-g2 Th~*h1)
play all play one stop play next play all
VL: A posteriori (AP)!
2.g8Q(R)+/Rg1+? Kf4 3.Qg5#??
Retro: d7-d5, Rc6xh6+ (unless Kg1-g2, Rh~-h1+).
One of the best AP-type problems. (2015-08-20)
James Malcom: The first Valladao AP? (2020-10-03)
A.Buchanan: Hi James, there are 6 earlier ones in PDB, not counting those which are not marked as Valladao (could quite a few, as basic AP is 2/3 of Valladao). Type k='a p' and not g='fairies' and k='valladao', and set sort order by date. The ur-problem is P0003417. (2020-10-03)
more ...
Keywords: Castling (wk), a posteriori (AP), En passant as key, Promotion (ws), Valladao Task (w w w/s)
Genre: Retro, 3#
Computer test: Popeye v4.85 + minor retro/AP thought
FEN: B7/p5PP/p6R/Q1Pp4/8/PP1P2P1/p3P1k1/4K2R
Reprints: (B) Die Schwalbe 48 12/1976
feenschach 40 11-12/1977
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2020-10-03 more...
2 - P0001146
W. Wolf
Deutsches Wochenschach 23/04/1911
1. bxc6ep e4 2. Se3 Kxg5 3. Kxd6
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Henrik Juel: C+ Popeye 4.61 (the three threats never materialize)
It is obvious that last move was c7-c5 (2020-12-02)
Keywords: En passant as key
Genre: Retro
FEN: 4B1R1/3NP1Pp/1Q1p1Prr/RPpKpNPk/6p1/6P1/P2B4/8
Reprints: 41 Volksgemeinschaft (Heidelberg) 19/01/1936
252 Comoedia 21/06/1936
22 Europe Echecs 18 02/1960
Input: Gerd Wilts, 1995-06-03
Last update: Mario Richter, 2020-12-02 more...
3 - P0003337
Rudolf Buljan
Problem 41-44 03/1957
2. Preis
15. Thematurnier
(11+15) C+
1. ... exf6ep 2. Sf5 f7#
play all play one stop play next play all
Autor Ing. Rudolf Buljan, Zagreb
Henrik Juel: Analysis
White captured fxg and promoted [Pd2] on d8
Black captured axbxa2-a1=Y, b7xc6, d5xe4, and gxf
The retroplay was R: 1... f7-f5 2.f5xYg6
C+ Popeye 4.61 (2020-09-30)
A.Buchanan: Any ideas how to distinguish usage of “whose move?” and “no legal last move for white” (or black) keywords (2020-10-01)
Henrik Juel: This problem is clearly the latter
I would use 'Whose move?' in retro problems where a deeper analysis is required to determine the move, often with stipulations like '#1 (who?)' (2020-10-01)
Keywords: En passant as key, No legal last move for White
Genre: h#, Retro
Computer test: Popeye 4.61
FEN: 5nkb/1qp1p1n1/2p3PQ/4PpKb/4prRp/P4prB/1PP3PP/8
Input: Gerd Wilts, 1995-06-03
Last update: James Malcom, 2020-10-01 more...
4 - P0003417
John Frederick Keeble
2206 The Problemist FCS 16, p. 173, 02/1936
(4+5) C+
Weiß zieht an
1. ... exd6ep 2. 0-0-0 dxe7+ 3. Tf8 exf8=T,D#
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H.Juel: If Black may castle, last move was not made by Ke8 or Ta8, but by Pd5, so it was d7-d5, and hence White may capture en passant. 1... exd6ep 2.0-0-0 dxe7 3.Tf8 exf8=DT# where the castling (belatedly) justifies the e.p. capture.
Not 1... exd6ep 2.Kd8? dxe7 3.Kc8 e8=DT
C+ by Popeye 4.61, except for the promotion mate dual, which was considered acceptable in the old days.
Nachdruck in "Die Schwalbe" 33 mit Diagrammfehler (wBe6 fehlt).
VL: The first AP-problem! Thematic illegal try:
1. ... exd6ep 2.Kd8? dxe7+ 3.Kc8 e8=T(D)#?? (2007-02-11)
Mario Richter: 46 years between this Problem and P1366663 - perhaps this was not Keeble's first AP-Problem?! (2019-08-29)
Ladislav Packa: Of course I know the idea a posteriori. But let my heresy be forgiven - I do not consider it logical. In this particular example, I consider e.p. for proof that black can castling - not vice versa. (2019-08-29)
A.Buchanan: Hi Ladislav. If ep is ok, then Black just moved a pawn with double hop. That doesn't stop Black having e.g. moved bK right at the beginning of the game. So you can't prove that Black definitely can castle this way. What am I missing here? (2019-08-29)
Ladislav Packa: Your statement is perfectly fine. However, the AP condition is usually interpreted as castling is evidence of e.p. However, the second party does not have to do castling - the possibility has already been demonstrated by the existence of e.p. (2019-08-29)
A.Buchanan: Hi again Ladislav. Please try again, I am obviously being very stupid. I don't understand how 1. exd6ep is any more indicative that Black can castle than 1. K~. (2019-08-30)
Ladislav Packa: Hi, Andre!
e.p. is just a result of the d7-d5 move. Black can castle only if it was the last move of black (even without wPe5). Therefore, it does not have the logic of joining the e.p. with castling. For example, ask yourself if black is allowed to castle in the position without wPe5. (2019-08-30)
A.Buchanan: Hi Ladislav, I still don't understand you. Heresies must be explained extraordinarily carefully :-)
Following the conventions:
(1) Black retains castling rights because we cannot prove that bK or bR ever moved.
(2) If e.p. is now played, then we still require the same castling convention, as bK or bR might have moved earlier in the game.
(3) So the actual execution of the e.p. does not prove anything new about castling.
(4) Hence it is incorrect to say "e.p. [is] proof that black can [castle]".
Which step do you disagree with?
Yes by the convention, Black could castle in the position without wPe5. What does that prove? (2020-10-03)
more ...
Keywords: a posteriori (AP), En passant as key, Castling (sg), Promotion (T), Valladao Task
Genre: h#, Retro
Computer test: Popeye 4.61
FEN: r3k3/2p1p3/2P1P3/2KpP3/8/8/8/8
Reprints: V. Die Schwalbe 33, p. 323, 06/1975
2001 CHM Themes 12/2000
3 Die Schwalbe 215, p. 240, 10/2005
A1 Problemkiste 169 02/2007
14 Die Schwalbe 241, p. 374, 02/2010
Input: Gerd Wilts, 1995-06-03
Last update: Alfred Pfeiffer, 2018-01-03 more...
5 - P0003423
Matti Arvo Myllyniemi
3975 Stella Polaris 01/1971
h#3 (AP)
1. ... g6 2. 0-0 gxf7 3. Kh8 Le5#
1. ... cxb6ep 2. 0-0-0 bxa7 3. Td7 a8=D#
play all play one stop play next play all
Henrik Juel: Analysis
If Black can castle both ways, last move must have been b7-b5
C+ Popeye 4.61 (2020-10-25)
Keywords: a posteriori (AP), En passant as key, Castling (sksg), Promotion (D), Valladao Task
Genre: h#, Retro
FEN: r3k2r/p4p1p/8/KpP2PP1/4PBpP/5pp1/6p1/8
Reprints: Nordisches Turnier 1970-1971
Input: Gerd Wilts, 1995-06-03
Last update: James Malcom, 2020-10-25 more...
6 - P0577550
Johann J. Chaschtschanski
14447 Schach , p. 79, 03/2000
b) sTc2 nach h6
a) 1. Txg2 Kxg2 2. Ld4 Kh1 3. Le5 fxe5 4. Kf4 e6 5. Kg5 e7 6. Kh4 e8=D 7. Kh3 Dxh5#
b) 1. gxf3ep gxf3 2. Ke5 Kg2 3. Le4 fxe4 4. Kf6 exf5 5. Kg7 f6 6. Kh8 f7 7. Th7 f8=D#
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Anton Baumann: C+ Gustav 4.1d (2020-11-24)
Keywords: Switchback (K in a), Entblockung, Promotion (D), Promotion in the mating move (D in b), Twin, En passant as key, Selfblock (in b), Corner mate (in b), Model mate (in b)
Genre: h#, Retro
FEN: 8/8/8/5p1p/4kPp1/3bb1p1/2r3Pp/7K
Input: hpr, 2000-10-27
Last update: Gunter Jordan, 2020-11-25 more...
7 - P1000901
Tomislav Petrovic
3 feenschach 137, p. 340, 08-09/2000
Zdravko Maslar gewidmet
(14+8) C+
1. dxc6ep!
1. ... dxc6+ 2. Lxc6 Sc7#
1. ... d6 2. d5 Sc7#
1. ... d5 2. exd5 Sc7#
1. ... dxe6 2. e5 Sc7#
1. ... gxf6 2. Sf5 Sc7#
1. ... g6 2. Lxg6 Sc7#
1. ... g5 2. Sg4 Sc7#
1. ... gxh6 2. Lh5 Sc7#
play all play one stop play next play all
James Malcom: This is a most excellent problem! En passant as the key and a double pickaninny in a short s#2 is surely no easy feat, I'd say. Now, question: Why can't dxc5 be Black's last move? The illegal retraction od b6-b7 is already quite obvious. (2020-10-24)
A.Buchanan: R: 1. cxb6/dxc5? both imply 3 pawn captures by Bl (2020-10-24)
A.Buchanan: I agree this is a beautifully integrated composition (2020-10-24)
more ...
Keywords: En passant, Pickaninny (2x), En passant as key, grab
Genre: Retro, s#
Computer test: C+ Popeye 4.61 after retro-analysis shows that last move was c7-c5
FEN: n2RB3/k2p2pR/Pp2PP1N/bKpP4/PpNPP3/1P6/8/8
Input: Gerd Wilts, 2000-10-08
Last update: A.Buchanan, 2020-10-25 more...
8 - P1181239
Thomas R. Dawson
The Chess Amateur 12/1923
Asymmetrie-Turnier 1924
1. Preis
(15+10) C+
1. gxf6ep+ Kxe8 2. Dg6+ hxg6 3. cxd8=S ... 4. f7+ Ke7 5. Sxg6+ Sxg6#
play all play one stop play next play all
Schwarz hat zuletzt f7-f5 gezogen, da d7-d5 an der retrograden Einsperrung des Lc8 scheitert.
Henrik Juel: C+ Popeye 4.61 after analysis
White is missing one man, so last move was not a pawn capture
White pawns captured all six missing black men, so last move was not d7-d5
Obviously last move was not made by Ke7 or Sd8f8, so last move was f7-f5 legitimizing the ep key (2020-11-02)
Keywords: Asymmetrical solution, En passant as key, Symmetrical position, Promotion (S)
Genre: Retro, s#
Computer test: C+ Popeye 4.61 after analysis
FEN: 1NRnBnRN/1pP1k1Pp/4p3/2PpKpP1/2pPQPp1/8/2P3P1/8
Reprints: 87 Asymmetry 1927
199 Mat Plus Review 01-06/2010
H2 ASymmetrie 2013
Input: Frank Müller, 2010-11-25
Last update: A.Buchanan, 2020-11-03 more...
9 - P1288715
Bernd Schwarzkopf
A12 Problemkiste (169) 02/2007
(4+3) C+
1. dxc6ep 0-0-0 2. b7+ Kb8 3. c7+ Kxb7 4. cxd8=D Ka7 5. Dc8=
3. ... Ka7 4. cxd8=S Kb8 5. Ka6,Kb6=
play all play one stop play next play all
A.Buchanan: Guessing so-called "AP-Priorität" is a variant of AP whereby Black is forced to legitimize (or at least forbidden to rule out the possibility of legitimizing) the earlier e.p. (2020-10-03)
Keywords: En passant, a posteriori (AP), Castling, En passant as key, Promotion, Valladao Task
Genre: Retro, Fairies
Computer test: Popeye v4.85 + minor retro/AP thinking
FEN: r3k3/8/1P1P4/1KpP4/8/8/8/8
Input: Erich Bartel, 2014-09-29
Last update: A.Buchanan, 2020-10-03 more...
10 - P1375286
Andrew Buchanan
James Malcom

PDB Website 30/4/2020
1. dxc7ep! b4 2. c8=D,T#

R: 1. ... c8-c6?! and earlier c8=sB
play all play one stop play next play all
Superseded by P1380851

Related: http://www.matplus.net/start.php?px=1577108437&app=forum&act=posts&fid=xshow2&tid=2395

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)
more ...
Keywords: En passant, 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, 2020-10-12 more...
11 - P1380523
Nels H. Nelson
760 Los Angeles Times , p. 30, 28/3/1937
"April Fool Joke"
1. gxh6ep+! Kxf7 2. 0-0xg1! Sf6 3. e8=sS#!
play all play one stop play next play all


We have heretofore published many of Nelson's fine problems and should like to show any readers the more humorous side of his talent. This winter our distinguished friend is spending his vacation in Los Angles. It is with his kind permission that we are publishing this story and problem.

Nels Nelson, born in Denmark in 1871, emigrated to the United States when 12 years of age. He learned the moves of chess in Denmark and began solving and composing problems in 1894. He was chess editor of the Minneapolis State Chess Asccostion, 1911-1912, president of the Minnesota State Chess Asccostion, 19229-1930, and lives at Hopkins, Minn., a suburb of Minneapolis.


A certain celebrated chess master, who we will designate as Mr. "X," while on in the provinces happended into a tavern which was the mecca of the village chess players. Mr. "X," very fond of practical jokes, concieved a plan of sprining on one of the unsuspecting natives. Professing ignorance of the game, the champion of the club offered to teach Mr. "X" its intricacies. After showing Mr. "X' all of the moves with the exception of pawn promotion, pawn takes pawn, etc., and castling, the champion said the following: ""I have purposely ommited three of the manuvers in chess, which to the beginner are somewhat difficult to grasp. They are pawn promotion-when a pawn reaches the eigth rank it ceases to be a pawn but may but it may be converted to any piece on the board and assumes its function at once. It it thus theortically possible to have as many as nine queens on the board at once, and so on down the line." The champion then went to explain the castling on the king and queen side and emphasised the importance of moving the king first. The act of pawn takes pawn "en passant" was then throughly explained and the actual game started with the champio givng odds of queen to Mr. "X," who proved to be a very apt pupil! Mr. "X" lost the first game in short order-walking boldy into a mating net. In the second game he gave the champion quite the battle and won the approbation of that was worthy. In the third game, the champion managed to trap Mr. "X's" queen but had to give up two pieces for it and saw that he had a lost game but continued on in the hope that his expierenced opponent would make some mistake. When the game has reached the postion in the diagram the champion was dumbfounded to hear Mr. "X" announce mate in three moves. "Impossible!" exclaimed the champion. "You should win, of course, but mate in three cannt be done." "Well, if you have interpreted the move and rules correctly, I am certain I see a mate in three," said Mr. "X." "Of course I have interpreted the rules correctly, exclaimed the now irate champion: and I will lay you a wager of dinner for the members of the club that you fail to mate in three moves." "Done!" cried Mr. "X." By this time nearly ever member in the clubwas watching the game with interest. Now, who won this wager? It will be shown in the solution April 11."


"SOLUTION TO PROBLEM 760 by N. Nelson: "April Fool Joke."

White: K. on K1 R. on Q7, and KR1: Kt. on KB7 and KB8: B, on QB5: P. on K7, KKt5, and KKt2, Black: K. on KKt2: R. on KKt1: Kt. on K1: B. on KKt8: P. on KR4. (Wh. 9: BL. 5.)

Many members of the club were very fine players and felt their champion would win. Curiously, most of them were pulling for mr. "X," as the champion was somewhat of a braggard and if he won they felt they wouls be hearing about it for a long time. They were, therfore, keenly alert when Mr. "X" started to proceed the game. "My first move is pawn takes en passant," said the smiling Mr. "x." "Of course, I anticipated that move," replied the champion, "and I shall meet it with king takes knight." Oh well then I shall make for my second move, castle: taking the bishop," continued Mr. "X." "This move is according to your definition of castling, perfectly legitimate, as the king moves first, and the bishop being on the knight squar, certainly is subject to capture." "Well," replied the champion, "I must say your interpretation is far fetched, but I will grant you even this point as I fail to see how you mate on the next move: you evidently overlook the fact that when you promote the pawn the king will be able to capture it. Of course, I am forced to interpose my knight and it is pinned, but the king will still be able to take care of that promoted pawn. " Well," smiled Mr. "X," "I shall, however, mate you by pawn to king eight, discovering check, as I shall claim a black knight for the promoted pawn, which, according to your interpretation of pawn promotion, is perfectly legitimate. You stated I might choose any piece on the board and, of course, as the black knight is the only piece that will mate, I naturally selected it."
Exit champion.

We are publishing the best solution sent in my Ladderite L. A. Post, incidentally only two others solved this April Fool Problem.

Problem 760 to complete the tale that Mr. Nelson started to what I believe to be the logical solution according to the rules given by the local champion.
1. White: Pawn takes pawn "en passant" check.
The local champion then captured the white knight reposing on his "bishop two."
1. Black: king takes knight.
"Now," continued Mr. "X" "I understand to quote you, the king moves firstl in castling."
"That is correct," agreed the champion.
Thereupon Mr. "X" executed the move in the prescribed manner by first moving his king to his king knight square and removing the champion's bishop and then setting his rook down on his king bishop square calling check.
The champion was nonplussed, for in stating the rules for "castling" he had failed to forsee a circumstance of this kind. He was forced to admit that, according to his own statement, such a move was possible But seeing in spite of this that it was still impossible to checkmate on the next move, he conceded the point and interposed his knight.
2. Black: Knight to king bishop three.
"Did you not say," resumed Mr. "X," "that in 'pawn promotion' you could reclaim to any piece on the board?"
"That is correct," conceded the champion, "but since you insist on taking me literally I might add that there is no "queen' on the board you may claim in one."
"In that case," stated Mr. "X," "I will be equally generous and present you with a 'knight.'"Whereupon Mr. "X" removed the pawn at king seven and placed a black 'knight' at king eight discovring checkmate to the champion's "king."
"Such a thing is impossbile !" cried the outraged champion.
"Not at all," replied Mr. "X," "for according to your statement that "upon reaching the eight rank a pawn be converted to any piece on the board and assumes its function at once.'"
To this the other members agreed. So the champion held a dinner in honor of Mr. "X," the most apt pupil he had ever taught.

Resepctfully yours,

L.A. Post
Seaman, First Class, U.S. Navy,
U.S..S Texas, San Pedro, Cal."
Henrik Juel: Some help is needed here, James
At least for me (2020-10-01)
A.Buchanan: Hi Henrik I am guessing it’s a cheatyface Valladao:
1. gxh6ep+ Kxf7 2. 0-0+ Sf6 3. f8=sS#
No proof for the ep, castling with capture and promotion to black officer (2020-10-02)
James Malcom: Bingo Andrew! (2020-10-02)
Henrik Juel: Even though I ought to stand by my fellow danish author:
This is a most crude 'joke' problem, especially the 'castling' with capture (2020-10-02)
A.Buchanan: It's kind of a running gag: three silly jokettes which do combine relatively harmoniously (2020-10-02)
A.Buchanan: 1. ... Kf6 allows a short mate, robbing White of the Valladao. 4nNbn/3RP1kN/8/6Pp/8/8/8/4K1bR is the best I can find, fixing the problem, and with less material (2020-10-02)
A.Buchanan: I was hoping that someone would spot that I have shifted a unit to h7 - i.e. the e.p. is even more Foolish :-) I claim it "improves" the problem because currently the e.p. *might* be legal :-) If this is too crude for some, then 4nNr1/3RP1k1/6N1/4P1Pp/8/8/8/4K1bR works. Note you need sTg8 to prevent 2. Sh8#, but wSg6 is blocking g-file, so wBg2 is still free to find other duties on e5. (2020-10-03)
James Malcom: Excellent improvements, Andrew! (2020-10-06)
A.Buchanan: Thanks James: do you think the one with Sh7 is excessively silly? (2020-10-06)
James Malcom: Yes, 'd say a bit too silly. (2020-10-16)
more ...
Keywords: Joke, Valladao Task, Joke promotion (s), En passant as key, Castling, Checking key, under-promotion (s)
Genre: 3#
FEN: 4nNr1/3RPNk1/8/2B3Pp/8/8/6P1/4K1bR
Reprints: Los Angeles Times , p. 13, 11/4/1937
Input: James Malcom, 2020-10-01
Last update: Alfred Pfeiffer, 2020-10-16 more...
12 - P1380892
Courtnay Lemon
343 American Chess Magazine Volume 2, p. 284, 12/1898
1. bxc6ep+! Kc7 2. 0-0-0 Dxb4 3. a8=S#
play all play one stop play next play all
Solution text from the 2/1899 issue: "A clever rendering of this "triple idea." It will be seen that Black cannot play simply 2.R-Q sq on account of 3. Q x Q ch."
zum Autor heißt es im 'ACM': Courtenay Lemon, New York
James Malcom: I found this most excellent early Valladao while ago, but only today did I finally find it again. This is the second one that I've found, i.e. P1380523

Is this the second oldest known Valladao after the 1867 P1360420 found by Keym?

The mainline should be C+, with the "legitimate" ep key, but with many dualed sidelines. (2020-10-14)
Henrik Juel: Something seems missing, James
There is no mate 3... Kc8,Kxc6 (2020-10-14)
Henrik Juel: Adding wSe7 would help (2020-10-14)
James Malcom: Henrik, Mario-many thanks!-has now fixed the position. I had missed the wSe7 when entering! (2020-10-14)
Keywords: Joke (e.p.), En passant as key, Castling, under-promotion in mating move (S), Valladao Task
Genre: 3#
FEN: 1b6/Pk2N3/1q6/1Pp5/1Q6/4p1p1/2P5/R3K3
Input: James Malcom, 2020-10-14
Last update: Mario Richter, 2020-10-14 more...
13 - P1380992
Otto Gross
1 Aufbau (New York) 30/04/1943
(13+5) C+
1. gxf6ep! droht 2. Dg5#
1. ... gxh6 2. Sxh6#
1. ... Sf3+ 2. exf3#
1. ... Sxg2 2. e7#
1. ... Sxg6+ 2. Dxg6#
1. ... gxf6+ 2. Sxf6#
play all play one stop play next play all
'Aufbau': Das Problem des en-passant-Schlagens ist in unserer Aufgabe nicht die Schwierigkeit, der wir besonderen Wert beimessen, sondern es handelt sich lediglich darum, die Korrektheit der Stellung nachzuweisen, nämlich warum zuletzt nur f7-f5 von Schwarz geschehen sein kann.
f6-f5 oder Sh4-f3 kann nicht geschehen sein, sonst hätte der weisse König im Schach gestanden; die Möglichkeit, dass evtl. ein dritter Springer, in welchen der fehlende weisse Bauer umgewandelt wurde, bei der Placierung des schwarzen Königs auf g3 durch ein Abzugsschach (Sf2-g4 Kg3xg4) ermöglicht haben könnte, fällt fort, da der fehlende Bauer nur ein weisser Läufer geworden sein kann, der jetzt auf c8 steht. Der bei Beginn des Spiels vorhanden gewesene weisse Läufer muss auf seinem Platz geschlagen worden sein, da Be2 und g2 seine Entwicklung verhinderten.
SCHRECKE: Umwandlungsläufer wLc8! (2020-10-16)
Henrik Juel: C+ Popeye 4.61, after analysis proving that last move was f7-f5 (2020-10-16)
Keywords: En passant as key, Obtrusive material
Genre: 2#, Retro
Computer test: Popeye 4.61
FEN: 2B3N1/2P3p1/4P1PQ/4KpPp/5Pkn/8/3NP1P1/4B3
Input: Mario Richter, 2020-10-16
Last update: Alfred Pfeiffer, 2020-10-17 more...
14 - P1381271
I. I. Lyon
No. 9 American Chess Review Vol. 1, p. 27, 8/1886
1. exf6ep! droht 2. Sc6,Se6#
1. ... Sd6,gxf4 2. Se6#
1. ... Sc7,Sxf6,Sg7 2. Sc6#
play all play one stop play next play all
Henrik Juel: The ep key is unjustified (2020-10-24)
more ...
Keywords: En passant, En passant as key, Joke
Genre: 2#
FEN: 3kn3/8/1N6/4PppB/3N1B2/8/3K4/8
Input: James Malcom, 2020-10-24
Last update: A.Buchanan, 2020-10-25 more...
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The problems of this query have been registered by the following contributors:

Gerd Wilts (6)
hpr (1)
Frank Müller (1)
Erich Bartel (1)
James Malcom (4)
Mario Richter (1)