34 problem(s) found in 1442 milliseconds (displaying 34 problem(s)). [k='bosma'] [download as LaTeX]

1. g6! Sd7+ 2. Kf7+! Sxe5+ 3. g7+! Kh7 4. g8=D+ Kh6 5. Dg7#

This problem was sent to CHESS Magazine, known as Pergamon Chess at the time. See https://twitter.com/Berlin_Endgame/status/1271456213889355778

"Dear Sir,

I have composed a miniature which seems to cause some controversy among those I have shown it to: (diagram) White to play and win.

Neither I nor my computer can find an appropriate forcing sequence after a queen or king move. By default: 1. g6 Nd7+ 2. Kf7 Nxe5+ 3. g7+

I am convinced that this is legal. Article 9.1 of the Laws of Chess states that "a king is in check when the square if occupies is attacked by one or two pieces." This wording specifically eliminates the possibility of the king being of check when it is attacked by three pieces. Therefore White's third move is in accordance with Article 9.2: "check must be parried by the move immediately following."

The remaining play is trivial: 3... Kh7 4. g8=Q+ Kh6 5. Qg7#

It is not too far-fetched to suppose that such a situation could arise in a game. The FIDE Rules Commission should therefore be invited to change the wording of Article 9.1 at Thessaloniki. If you agree, or think the problem is sufficiently amusing, it would give my great pleasure to see it published in your magazine.

ROBERT NORMAN,

Dar es Salaam, Tanzania

April 11, 1988"

(See P1377133 for another version.)

AB: As an orthodox study, these days we know definitively by tablebase that the position is a draw. But in WinChloe, we can run the Bosma condition but realistically only as a directmate. As a #7 WinChloe gave:

1. g6? [2. Qe8#]

1. ... Sd7+ 2. Kf7+ Sf6+ 3. Kf8 [4. Qxf6+ Rg7 5. Qxg7#] Rf7+ 4. Kxf7 [5. Qxf6#] Bxg6+ 5. Kxg6

[6. Qe7 [7. Qg7#] Se8 7. Qh7/Qxe8/Qf8#

6. ... Sh5 7. Qh7/Qe8/Qd8/Qf8#

6. Qxf6+ Kg8 7. Qd8/Qg7#]

So there is no mention of the intended (short) solution after 2. ... Sxe5+ 3. g7+ Kh7 4. g8=Q+ Kh6 5. Qg7#

but 1. ... Kg8!

The point now is 2. Qe8+? Kf7+! 3. K~5 Kxe8! winning for Black. I have had WinChloe analyze both the original position, and that after 1. g6 Kg8 as #8, and there is no other solution or try. I think that as a study it's probably still a win for White, who following 1. ... Kg8 also has e.g. 2. Qd5/Qf6+ Kf7+ 3. K~5+ etc, but how long would it take as a directmate? Any ideas? And can anyone confirm definitively that the study is cook-free?

This problem was sent to CHESS Magazine, known as Pergamon Chess at the time. See https://twitter.com/Berlin_Endgame/status/1271456213889355778

"Dear Sir,

I have composed a miniature which seems to cause some controversy among those I have shown it to: (diagram) White to play and win.

Neither I nor my computer can find an appropriate forcing sequence after a queen or king move. By default: 1. g6 Nd7+ 2. Kf7 Nxe5+ 3. g7+

I am convinced that this is legal. Article 9.1 of the Laws of Chess states that "a king is in check when the square if occupies is attacked by one or two pieces." This wording specifically eliminates the possibility of the king being of check when it is attacked by three pieces. Therefore White's third move is in accordance with Article 9.2: "check must be parried by the move immediately following."

The remaining play is trivial: 3... Kh7 4. g8=Q+ Kh6 5. Qg7#

It is not too far-fetched to suppose that such a situation could arise in a game. The FIDE Rules Commission should therefore be invited to change the wording of Article 9.1 at Thessaloniki. If you agree, or think the problem is sufficiently amusing, it would give my great pleasure to see it published in your magazine.

ROBERT NORMAN,

Dar es Salaam, Tanzania

April 11, 1988"

(See P1377133 for another version.)

AB: As an orthodox study, these days we know definitively by tablebase that the position is a draw. But in WinChloe, we can run the Bosma condition but realistically only as a directmate. As a #7 WinChloe gave:

1. g6? [2. Qe8#]

1. ... Sd7+ 2. Kf7+ Sf6+ 3. Kf8 [4. Qxf6+ Rg7 5. Qxg7#] Rf7+ 4. Kxf7 [5. Qxf6#] Bxg6+ 5. Kxg6

[6. Qe7 [7. Qg7#] Se8 7. Qh7/Qxe8/Qf8#

6. ... Sh5 7. Qh7/Qe8/Qd8/Qf8#

6. Qxf6+ Kg8 7. Qd8/Qg7#]

So there is no mention of the intended (short) solution after 2. ... Sxe5+ 3. g7+ Kh7 4. g8=Q+ Kh6 5. Qg7#

but 1. ... Kg8!

The point now is 2. Qe8+? Kf7+! 3. K~5 Kxe8! winning for Black. I have had WinChloe analyze both the original position, and that after 1. g6 Kg8 as #8, and there is no other solution or try. I think that as a study it's probably still a win for White, who following 1. ... Kg8 also has e.g. 2. Qd5/Qf6+ Kf7+ 3. K~5+ etc, but how long would it take as a directmate? Any ideas? And can anyone confirm definitively that the study is cook-free?

1. ... Sc4+ 2. Sf7#!

The original text was found preserved in an old, archived Google forum: https://groups.google.com/forum/m/#!topic/rec.games.chess/wCP3voSjXkw

“CHECK THIS OUT!

"Right, N. Short, J. Speelman, J. Nunn, and the rest of you clever clogs. Break your heart on this: White: Ke3, Qb2, Ne5 Black: Kh8, Re8, Rg8, Ba7, Nb6, Pg7, h7 Black incautiously played a double check 1...Nc4+?? How did White crash through to victory? Admit it; you're baffled. Deduct one hundred Elo points [and read on]:

Dead easy. White gets out of check by 2 Nf7 mate. Yes, it's perfectly legit. Consult Article 9.1 of the laws: "The King is in check when the square it occupies is attacked by one or two of the opponent's pieces..." It says nothing about a threefold attack, so White's move takes him out of check..." - Mike Fox and Richard James Addicts' Corner column, February, 1992 issue of "Maxwell Macmillan Chess" (One of many CHESS Magazine rebrands

Reprints:

https://www.ecforum.org.uk/viewtopic.php?f=2&t=10842&p=245798#p245798

https://chess.stackexchange.com/questions/29990/when-was-it-possible-for-a-players-king-to-be-attacked-by-3-of-the-opponents-p/29992#29992

The original text was found preserved in an old, archived Google forum: https://groups.google.com/forum/m/#!topic/rec.games.chess/wCP3voSjXkw

“CHECK THIS OUT!

"Right, N. Short, J. Speelman, J. Nunn, and the rest of you clever clogs. Break your heart on this: White: Ke3, Qb2, Ne5 Black: Kh8, Re8, Rg8, Ba7, Nb6, Pg7, h7 Black incautiously played a double check 1...Nc4+?? How did White crash through to victory? Admit it; you're baffled. Deduct one hundred Elo points [and read on]:

Dead easy. White gets out of check by 2 Nf7 mate. Yes, it's perfectly legit. Consult Article 9.1 of the laws: "The King is in check when the square it occupies is attacked by one or two of the opponent's pieces..." It says nothing about a threefold attack, so White's move takes him out of check..." - Mike Fox and Richard James Addicts' Corner column, February, 1992 issue of "Maxwell Macmillan Chess" (One of many CHESS Magazine rebrands

Reprints:

https://www.ecforum.org.uk/viewtopic.php?f=2&t=10842&p=245798#p245798

https://chess.stackexchange.com/questions/29990/when-was-it-possible-for-a-players-king-to-be-attacked-by-3-of-the-opponents-p/29992#29992

**Keywords:**Golden Age, Joke, Bosma

**Genre:**n#

**Computer test:**C+ WinChloe 3.51

**FEN:**4r1rk/b5pp/1n6/4N3/8/4K3/1Q6/8

**Input:**James Malcom, 2020-06-20

**Last update:**A.Buchanan, 2020-11-26 more...

1. Kf7! droht 2. Txh5#

1. ... Sd6+,Sd8+ 2. g7+ Kh7 3. g8=D+ Kh6 4. Dg7#

A beautiful version of P1377131

http://faroffchess.blogspot.com/2008/12/in-twilight-zone-of-chess-rules.html

"Ok, you may say that this is all old stuff, very entertaining but with no relevance for nowadays chess. So? Well, look at this endgame study which circulated among the chess insiders in the 80s:

White to move and win - my version (from memory)

I believe I have read somewhere that the composer is from Dar-Es-Salaam, but I can not find sources for that.

The solution is: 1. Kf7, Nd6+ 2. g7+!, Kh7 3. g8D+ and mate next move.

Then you may object that white is in check, in fact a double check, when he unaffectedly moves his little pawn at the second move. Yes, he is in check BEFORE the move, but is he after? You see, at that time the rules stated that the king is in check "...when the square it occupies is threatened by one or TWO of the opponents pieces." So the check is elegantly parried by making the kings square threatened by THREE pieces!

Relax, nowadays the rules state that the square in question must be threatened by "... if one or more of the opponents pieces."

1. ... Sd6+,Sd8+ 2. g7+ Kh7 3. g8=D+ Kh6 4. Dg7#

A beautiful version of P1377131

http://faroffchess.blogspot.com/2008/12/in-twilight-zone-of-chess-rules.html

"Ok, you may say that this is all old stuff, very entertaining but with no relevance for nowadays chess. So? Well, look at this endgame study which circulated among the chess insiders in the 80s:

White to move and win - my version (from memory)

I believe I have read somewhere that the composer is from Dar-Es-Salaam, but I can not find sources for that.

The solution is: 1. Kf7, Nd6+ 2. g7+!, Kh7 3. g8D+ and mate next move.

Then you may object that white is in check, in fact a double check, when he unaffectedly moves his little pawn at the second move. Yes, he is in check BEFORE the move, but is he after? You see, at that time the rules stated that the king is in check "...when the square it occupies is threatened by one or TWO of the opponents pieces." So the check is elegantly parried by making the kings square threatened by THREE pieces!

Relax, nowadays the rules state that the square in question must be threatened by "... if one or more of the opponents pieces."

**James Malcom**: What is the Winchloe solution then, even with duals? Of course, as an endgame study, it is still correct. (2020-11-13)

**A.Buchanan**: As a #4, WinChloe gives: 1.Rf7! [2.T×h5‡]

1…Cd8+ 2.g7+ Rh7 3.g8=D+ Rh6 4.Dg7‡

1…Cd6+ 2.g7+ Rh7 3.g8=D+ Rh6 4.Dg7‡

Switchback blanc

Switchback de Pion

Echecs croisés

Guidelli

Echec double

Batterie noire

Auto-clouage indirect

Déclouage indirect

Promotion

Clé désampliative (2020-11-26)

more ...

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**Keywords:**Golden Age, Joke, Bosma, Promotion (D)

**Genre:**n#

**Computer test:**C+ WinChloe v3.51

**FEN:**7k/rn6/5KP1/p1p4b/8/8/8/7R

**Input:**James Malcom, 2020-06-20

**Last update:**A.Buchanan, 2020-11-26 more...

1. Dxc4+! Sxc4+ 2. Lf5+! Kd8 3. Lxe7+ Ke8 4. Lg6#

The joke is that the White king is legally exposed to a triple check under the 1983-1993 FIDE rules books. But instead of a triple check, here the White king is exposed to a quadruple check in the end position!

https://www.ecforum.org.uk/viewtopic.php?f=2&t=10842&start=30

The joke is that the White king is legally exposed to a triple check under the 1983-1993 FIDE rules books. But instead of a triple check, here the White king is exposed to a quadruple check in the end position!

https://www.ecforum.org.uk/viewtopic.php?f=2&t=10842&start=30

**James Malcom**: Whenever new territory comes up,I always sail my boat. I created this when someone asked if a quadruple check was possbile in the forum. (2020-06-20)

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**Keywords:**Golden Age, Joke, Bosma, Capture key, Checking key

**Genre:**n#

**Computer test:**WinChloe 3.51 C+

**FEN:**b1k2N2/P3p3/P2P4/4K1Br/1Qn1B3/8/1n6/b3r3

**Input:**James Malcom, 2020-06-20

**Last update:**A.Buchanan, 2020-11-08 more...

1. Tc8! droht 2. Te8# 2. f8=T,D+? Kd8! 2. f8=L,D+? Kd6! 2. f8=S+? Kxd7!

1. ... Ld8 2. f8=T#, 2. f8=L,D+? Kd6! 2. f8=S+? Kxd7!

1. ... Dxd7 2. f8=S#, 2. f8=T,D+? Kd8! 2. f8=L,D+? Kd6!

1. ... Sd6 2. f8=L#, 2. f8=T,D+? Kd8! 2. f8=S+ Kxd7!

https://www.chessvariants.com/problems.dir/bosma.html

"In 1993, Dutch chess problem composer R. Bosma noted in the FIDE-rules article 9.1, which stated:

The King is in check when the square on which it is standing is attacked by one or two enemy pieces.

Thus from this rule, it appears that a king is not in check when its square is attacked three or more times. This inspired Bosma to the following fairy chess form, called Bosma chess: A king that is attacked three or more times is not considered to be in check."

1. ... Ld8 2. f8=T#, 2. f8=L,D+? Kd6! 2. f8=S+? Kxd7!

1. ... Dxd7 2. f8=S#, 2. f8=T,D+? Kd8! 2. f8=L,D+? Kd6!

1. ... Sd6 2. f8=L#, 2. f8=T,D+? Kd8! 2. f8=S+ Kxd7!

https://www.chessvariants.com/problems.dir/bosma.html

"In 1993, Dutch chess problem composer R. Bosma noted in the FIDE-rules article 9.1, which stated:

The King is in check when the square on which it is standing is attacked by one or two enemy pieces.

Thus from this rule, it appears that a king is not in check when its square is attacked three or more times. This inspired Bosma to the following fairy chess form, called Bosma chess: A king that is attacked three or more times is not considered to be in check."

Preisrichter: "A nice and cool problem in excellent minor promotions, which immediately appealed to me. These promotions cannot be realized in an ordinary problem."

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**Keywords:**under-promotion (TSL), Bosma

**Genre:**Fairies, 2#

**Computer test:**C+ WinChloe 3.51

**FEN:**7K/1NRNkP1R/5p2/b1P2B2/2n5/8/8/3q4

**Reprints:**MatPlus.net Forum 13/7/2020

**Input:**James Malcom, 2020-06-20

**Last update:**A.Buchanan, 2020-11-18 more...

1. Dd3+! Sxd3+ 2. Se6+! Kxe8 3. Sf6+ Kf7 4. Tg7#

https://www.ecforum.org.uk/viewtopic.php?p=247325&sid=c5155a78a8fb488f8ca3aeccd91c0e36#p247325

https://www.ecforum.org.uk/viewtopic.php?p=247325&sid=c5155a78a8fb488f8ca3aeccd91c0e36#p247325

**James Malcom**: During a Zoom meeting a fews days ago, I showed P1377134 as a demonstration of the legal triple check to Marken Foo, and he remarked that +wRg2 wLg8 & sSf4 produces a #5 with a quintuple check,-4... Sxg6+ 5. Lf7#-but with prmoted pieces. I saw potential for a third pin, and here is my successful end result. I also managed to avoid putting the White king in check. (2020-06-21)

more ...

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**Keywords:**Golden Age, Joke, Bosma, Sacrifice key

**Genre:**n#

**Computer test:**WinChloe 3.51 C+

**FEN:**1RnkBB2/2p5/8/4K1Nr/4N3/6R1/1n5q/bQ2r3

**Input:**James Malcom, 2020-06-21

**Last update:**A.Buchanan, 2020-11-08 more...

1. Tf5+! Sxf5+ 2. Se4+! Sxe4 3. De6#

**James Malcom**: I've added in the solution now. (2020-11-02)

**Henrik Juel**: Thanks, James

I cannot test the problem, but it seems OK (2020-11-02)

**A.Buchanan**: Thanks Henrik: it's C+ according to WinChloe (2020-11-03)

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**Keywords:**Aristocrat, Bosma

**Genre:**3#, Fairies

**Computer test:**C+ WinChloe v3.51

**FEN:**3r2R1/3Q4/3K1k2/2n1R3/1b6/6n1/3N3q/3r4

**Input:**A.Buchanan, 2020-10-25

**Last update:**A.Buchanan, 2020-11-03 more...

1. 0-0#!

https://chess.stackexchange.com/a/29992/15543

https://chess.stackexchange.com/a/29992/15543

**A.Buchanan**: Hi James, couple of nits about old Bosma:

(1) From the 1985 Laws: "Article 5. THE MOVES OF THE PIECES The King (a) Except when cast[l]ing, the king moves to any adjoining square that is not attacked by an opponent's piece." This is separate from Article 9. CHECK 9.1 "The king is In check when the square it occupies is attacked by one or two of the opponent's pieces; in this case the latter is or are said to be "checking the king.' 9.2 Check must be parried by the [move] immediately following." This point may have been an assumption in earlier compositions, as e.g. it prevents kings from being adjacent.

(2) And again from Article 5. "(f) Castling is prevented for the time being - (i) if the king's original square or the square which the king must cross over or that which it is to occupy is attacked by an opponent's piece," Does this prevent your 1.0-0?

What do you think? (2020-11-08)

**James Malcom**: Ah, why did I but never bother to look at the castling rules!

Well I see nothing against adjacent kings, and seeing about how the "loophole" was about was not explicitly stated couldn't be done, I see it as allowed, and thus what to watch out for in cooks.

The rule on castling says "piece," not pieces. So, quite simply, castling in, out (P1381498), and through (P1381499) check is allowed in my view. (2020-11-09)

**James Malcom**: Furthermore, if a king is "attacked," they are in check, plain and simple. So, since a triple check/ attack is not defined as a danger to the king, the king may go to any such square, including the acts of catling and adjacent kings.

Also, going by the law itself, and not the Bosma conditions, the king may be captured, but it does nothing and that side can never be checkmated, while Bosma Chess itself allows no king capture. But since the effect is the same, allowing for my jokes to be C+ by Winchloe if the program agrees. Maybe try out my castlings in it? (2020-11-09)

**James Malcom**: And indeed Andrew has tested my castling problems now-all are C+? (2020-11-14)

**James Malcom**: Typo-!, not ?. (2020-11-14)

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1. Sf5+! Kxf3 2. 0-0#

https://chess.stackexchange.com/a/29992/15543

https://chess.stackexchange.com/a/29992/15543

1. 0-0+!

1. ... Shxf1 2. Dg4#

1. ... Sgxf1 2. Df2#

1. ... Lxf1 2. Tf2#

https://chess.stackexchange.com/a/29992/15543

1. ... Shxf1 2. Dg4#

1. ... Sgxf1 2. Df2#

1. ... Lxf1 2. Tf2#

https://chess.stackexchange.com/a/29992/15543

**A.Buchanan**: Nice way to combine an orthodox theme with Bosma castling (2020-11-13)

**James Malcom**: Thanks, Andrew. Castling with check is the easiest way to achieve it of course, not to mention the flight taking. I'll try out a version without check, here soon. (2020-11-13)

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**Keywords:**Joke, Bosma, Castling as key, Checking key, x pieces capture on one square, Flight taking

**Genre:**2#

**Computer test:**C+ WinChloe 3.51

**FEN:**8/8/8/5B2/5p1Q/5kn1/2NRb2n/4K2R

**Input:**James Malcom, 2020-11-03

**Last update:**James Malcom, 2020-11-13 more...

1. Kc2#!

https://www.ecforum.org.uk/viewtopic.php?p=246809#p246809

Reprint: https://chess.stackexchange.com/a/29992/15543

https://www.ecforum.org.uk/viewtopic.php?p=246809#p246809

Reprint: https://chess.stackexchange.com/a/29992/15543

1. e4+! dxe3ep+ 2. Lxe6#

https://www.ecforum.org.uk/viewtopic.php?p=246809#p246809

Reprint: https://chess.stackexchange.com/questions/29990/when-was-it-possible-for-a-players-king-to-be-attacked-by-3-of-the-opponents-p/29992#29992

https://www.ecforum.org.uk/viewtopic.php?p=246809#p246809

Reprint: https://chess.stackexchange.com/questions/29990/when-was-it-possible-for-a-players-king-to-be-attacked-by-3-of-the-opponents-p/29992#29992

1. Se5#!

**A.Buchanan**: Trivial verification, perhaps, but at least it confirms that WinChloe's understanding of the condition resembles James'. (2020-11-13)

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14 - P1381880

Probleemblad 1993

1. Preis h#

151. Thematurnier

(5+4) C+

h#2

Bosma

b) wBd4->e3

c) ferner wBd3->e4

**Nikolay A. Zharkov**Probleemblad 1993

1. Preis h#

151. Thematurnier

(5+4) C+

h#2

Bosma

b) wBd4->e3

c) ferner wBd3->e4

a) 1. Dc5 d5 2. e1=T Kg1#

b) 1. Dxd3 e4 2. e1=L Kg3#

c) 1. Dd5 e5 2. e1=S Kg2#

b) 1. Dxd3 e4 2. e1=L Kg3#

c) 1. Dd5 e5 2. e1=S Kg2#

Preisrichter: "In a very subtle way three minor promotions emerge which appeal to me very much. Personally, I have a soft spot for problems like this."

What are the solutions?

I see a Bosma mate with Df5 on, say, c2, e1=S, and Kh2 on g2, but I cannot get there (2020-11-14)

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**A.Buchanan**: Are Nikolai Sharkow & Nikolai A. Sharkow the same person? The areas of interest seem sufficiently distinct that I didn't want to merge PDB composer IDs without confirmation. (2020-11-14)**Henrik Juel**: I expect that NS and NAS are identical, but who knows?What are the solutions?

I see a Bosma mate with Df5 on, say, c2, e1=S, and Kh2 on g2, but I cannot get there (2020-11-14)

**A.Buchanan**: Really rather nice twinning. WinChloe thinks these are the same guy, so I'll go with that. (2020-11-14)**Henrik Juel**: Certainly a worthy prize winner (2020-11-14)comment

**Keywords:**Bosma, under-promotion (t,l,s), Capture key

**Genre:**h#, Fairies

**Computer test:**C+ WinChloe 3.51

**FEN:**4N1rk/8/8/5q2/3P4/3P4/4p2K/7R

**Input:**A.Buchanan, 2020-11-14

**Last update:**A.Buchanan, 2020-11-18 more...

1. Sxb4! droht 2. d4#

1. ... Txb4+,f3+ 2. Kd4#

1. ... Sd6+,Txa3 2. Sa6#

1. ... Lxg5 2. Lxb6#

1. ... Txb4+,f3+ 2. Kd4#

1. ... Sd6+,Txa3 2. Sa6#

1. ... Lxg5 2. Lxb6#

16 - P1381882

Probleemblad 1993

1. ehrende Erwähnung

151. Thematurnier

(6+8) C+

#2

Bosma

**Robert Ketzscher**Probleemblad 1993

1. ehrende Erwähnung

151. Thematurnier

(6+8) C+

#2

Bosma

1. Sxd6? droht 2. Sb5#

1. ... cxd6 2. Lxd6#

aber 1. ... e1=D,T,L,S! 2. Sb5+ e2!

1. Sxe3? droht 2. Sc2#

1. ... fxe3 2. Txe3#

aber 1. ... La8,L~ 2. Sc2+ d5!

1. Sd4! droht 2. Sb5,Sc2#

1. ... e1=S,Le4 2. Sb5#

1. ... Lc6,Lxc4,c6 2. Sc2#

1. ... cxd6 2. Lxd6#

aber 1. ... e1=D,T,L,S! 2. Sb5+ e2!

1. Sxe3? droht 2. Sc2#

1. ... fxe3 2. Txe3#

aber 1. ... La8,L~ 2. Sc2+ d5!

1. Sd4! droht 2. Sb5,Sc2#

1. ... e1=S,Le4 2. Sb5#

1. ... Lc6,Lxc4,c6 2. Sc2#

Preisrichter: "This has a nice battery formation. I do not find the double threat annoying because it fits well with the tries, and the composer has incorporated this double threat."

Version at P1382047

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Version at P1382047

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**Keywords:**Bosma, under-promotion (s)

**Genre:**2#, Fairies

**Computer test:**C+ WinChloe 3.51

**FEN:**5B2/2p5/3p4/3b1N2/p1P2p2/k3p2R/4p3/KR6

**Input:**A.Buchanan, 2020-11-14

**Last update:**Alfred Pfeiffer, 2020-11-26 more...

17 - P1381883

Probleemblad 1993

2. Preis h#

151. Thematurnier

(10+10) C+

h#2

Bosma

2 solutions

**Bastiaan Evert de Haas**Probleemblad 1993

2. Preis h#

151. Thematurnier

(10+10) C+

h#2

Bosma

2 solutions

1) 1. Sd3+ e4 2. Sf4 Sdc5#

2) 1. Te8+ e3 2. Te6 Sf6#

2) 1. Te8+ e3 2. Te6 Sf6#

Preisrichter: "This one may be there too. It is more the classic kind of helpmate with many effects that are equal in both solutions."

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1. Dh2! droht 2. Db8#

1. Dg2? droht 2. Da8# aber Kxg7!

1. Da3? d2 2. Df8+ Kxg7!

1. Dg2? droht 2. Da8# aber Kxg7!

1. Da3? d2 2. Df8+ Kxg7!

1. Se7! zz

1. ... Lh5,Le8 2. Tg8#

1. ... Kg8,La2,Lb3,Lc4,Ld5,Le6 2. Seg6#

1. ... Lg6 2. Tg8,Sexg6#

1. ... Lg8 2. Txg8,Seg6,Sfg6#

1. ... Lh5,Le8 2. Tg8#

1. ... Kg8,La2,Lb3,Lc4,Ld5,Le6 2. Seg6#

1. ... Lg6 2. Tg8,Sexg6#

1. ... Lg8 2. Txg8,Seg6,Sfg6#

**Henrik Juel**: Popeye says 1.Se7 and 1.Sh6

How does the Bosma condition change this?

The intention is probably 1.Sh6, as 1.Se7 entails far more duals (2020-11-14)

**A.Buchanan**: 1. Sh6? fails to 1. Kg8,La2,...,Le6 as can't unoverload g8. 1.Se7! has duals after Lg6 & Lg8. This isn't great but in better shape than many of the others (2020-11-14)

**Henrik Juel**: Thanks, Andrew

The weird condition is trickier than I thought (2020-11-14)

**A.Buchanan**: Haha yes Henrik: they are hard to debug: because it's always unclear whether a piece, of either colour, is helping or hurting :) (2020-11-14)

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**Keywords:**Bosma, Aristocrat

**Genre:**2#, Fairies

**Computer test:**C+ WinChloe 3.51

**FEN:**5NNk/5bRB/5K2/8/8/8/8/8

**Input:**A.Buchanan, 2020-11-14

**Last update:**A.Buchanan, 2020-11-18 more...

20 - P1381886

MatPlus.net Forum 30/10/2020

RB, correction AB

(8+12) C+

#2

Bosma

**Rainer Paslack**

Andrew BuchananAndrew Buchanan

MatPlus.net Forum 30/10/2020

RB, correction AB

(8+12) C+

#2

Bosma

1. d7! droht 2. Kd6#

1. ... Lxg3+ 2. Kf4#

1. ... Sxf2 2. Ke4#

1. ... Th5+ 2. Kf5#

1. ... Te8+ 2. Ke6#

1. ... Txd7 2. Kd4#

1. ... Dxc5+ 2. Dxc5#

1. Db5? droht 2. Txc4,Dxc4#

1. ... Lc2!

1. ... Lxg3+ 2. Kf4#

1. ... Sxf2 2. Ke4#

1. ... Th5+ 2. Kf5#

1. ... Te8+ 2. Ke6#

1. ... Txd7 2. Kd4#

1. ... Dxc5+ 2. Dxc5#

1. Db5? droht 2. Txc4,Dxc4#

1. ... Lc2!

1. Tc3! zz

1. ... Txf4 2. Tc5#

1. ... Tg4 2. Sc7#

1. ... Txh3 2. Sc7#

1. ... Lxf3 2. Sf6#

1. ... Lg4 2. Sc7#

1. ... dxc3 2. Td1#

1. ... d3 2. Txd3#

1. ... Txb3 2. Le6#

1. ... Dxb4 2. Te5#

1. ... Dxb3 2. Le6#

1. ... Dxb5 2. Se7#

1. ... axb4 2. Te5#

Cook: 1. Td1! droht 2. Sf6,Sc7,Tc5#

1. ... d3 2. Txd3#

1. Td2! droht 2. Le6,Se7,Te5#

1. ... d3 2. Txd3#

1. ... Txf4 2. Tc5#

1. ... Tg4 2. Sc7#

1. ... Txh3 2. Sc7#

1. ... Lxf3 2. Sf6#

1. ... Lg4 2. Sc7#

1. ... dxc3 2. Td1#

1. ... d3 2. Txd3#

1. ... Txb3 2. Le6#

1. ... Dxb4 2. Te5#

1. ... Dxb3 2. Le6#

1. ... Dxb5 2. Se7#

1. ... axb4 2. Te5#

Cook: 1. Td1! droht 2. Sf6,Sc7,Tc5#

1. ... d3 2. Txd3#

1. Td2! droht 2. Le6,Se7,Te5#

1. ... d3 2. Txd3#

Preisrichter: "An impressive problem and a multitude of variants. The therefore also somewhat heavy position and the one dual 1 ... Kc5 or Ke5 is forgiven. A problem to play."

Correction at P1381912

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Correction at P1381912

**A.Buchanan**: This is a delightful problem, but cooked in the original. However it can be smoothly corrected by shifting wTc2 to c7 (and I don't see any other ways to do it). Alas the composer is no longer with us. (2020-11-14)comment

**Keywords:**Bosma, Superseded by (P1381912)

**Genre:**2#, Fairies

**Computer test:**C- WinChloe 3.51

**FEN:**2NQN3/8/1P1p2p1/pP1k2Pb/qP1p1P1r/rP3P1B/p1R5/K3R3

**Input:**A.Buchanan, 2020-11-14

**Last update:**A.Buchanan, 2020-11-18 more...

1. d7! droht 2. Kd6#

1. ... Lxg3+ 2. Kf4#

1. ... Sxf2 2. Ke4#

1. ... Th5+ 2. Kf5#

1. ... Te8+ 2. Ke6#

1. ... Txd7 2. Kd4,Kd5#

1. ... Dxc5+ 2. Dxc5#

Cook: 1. Da5+!

1. ... Sb4 2. Kd5#

1. ... Lxg3+ 2. Kf4#

1. ... Sxf2 2. Ke4#

1. ... Th5+ 2. Kf5#

1. ... Te8+ 2. Ke6#

1. ... Txd7 2. Kd4,Kd5#

1. ... Dxc5+ 2. Dxc5#

Cook: 1. Da5+!

1. ... Sb4 2. Kd5#

Preisrichter: "The beautiful key, variants and battery game have entranced me."

Correction at P1381886

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Correction at P1381886

comment

**Keywords:**Bosma, Superseded by (P1381886)

**Genre:**2#, Fairies

**Computer test:**C- WinChloe 3.51

**FEN:**3r4/5p1r/1QpP1Bp1/2R1K3/2q4p/1pk3Pn/n3RN1b/1b6

**Input:**A.Buchanan, 2020-11-14

**Last update:**A.Buchanan, 2020-11-18 more...

1. Db8! droht 2. S2c4+ Lxc4 3. Kd5#

2. ... Kxd6 3. Se5#

1. ... Lxd2 2. Sf7+ f4 3. Sd6#

2. ... c2 3. Sg5#

2. ... Kd6 3. Se5#

1. ... Txd2 2. Sc4+ f4 3. Sb2#

2. ... c2 3. Sd6#

2. ... Kd6 3. Se5#

Cook: 1. Sxb5+!

1. ... Txc7 2. Sd6 droht 3. S2c4,Sf7,S6c4#

2. Sd4 droht 3. Txe6,Sc4#

1. ... Kd6 2. Kc4+ e5 3. Dxc8#

1. Dc6! droht 2. Sf3+ exf3 3. De4#

2. Dd5+ exd5 3. Txf5#

2. Dxb5 droht 3. S2c4,Sf7,S6c4# Sc7+ 3. Kd5#

2. ... Kxd6 3. Se5#

1. ... Lxd2 2. Sf7+ f4 3. Sd6#

2. ... c2 3. Sg5#

2. ... Kd6 3. Se5#

1. ... Txd2 2. Sc4+ f4 3. Sb2#

2. ... c2 3. Sd6#

2. ... Kd6 3. Se5#

Cook: 1. Sxb5+!

1. ... Txc7 2. Sd6 droht 3. S2c4,Sf7,S6c4#

2. Sd4 droht 3. Txe6,Sc4#

1. ... Kd6 2. Kc4+ e5 3. Dxc8#

1. Dc6! droht 2. Sf3+ exf3 3. De4#

2. Dd5+ exd5 3. Txf5#

2. Dxb5 droht 3. S2c4,Sf7,S6c4# Sc7+ 3. Kd5#

**A.Buchanan**: Replacing sTc8 with sD eliminates one cook and simplifies the other, but 1. Sxb5+! Kd6 2. Kc4+ e5 3. Dxc8# remains. The intended solution is beautiful and ambitious - I suspect it must have been cooked before the prizes were awarded, otherwise to me it would be prize material. (2020-11-14)

**A.Buchanan**: Alternatively, shifting wD to b8 and wTg6 to g4 fixes everything, at the cost of a flight-taking key. On the other hand in Bosma every piece comes with a downside, and Black can use wTg6 as a defence, always threatening e6-e5 when bK has shifted to d6. This to some extent compensates for the crudeness of the key. This is an amazing problem and if it has been sound at the time, I would have given it first prize (2020-11-15)

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24 - P1381912

MatPlus.net Forum 14/11/2020

IM, correction AB

(14+10) C+

#2

Bosma

**Ion Murarasu**

Andrew BuchananAndrew Buchanan

MatPlus.net Forum 14/11/2020

IM, correction AB

(14+10) C+

#2

Bosma

1. Tc3! zugzwang

1. ... Txf4 2. Tc5#

1. ... Tg4 2. Sc7#

1. ... Txh3 2. Sc7#

1. ... Lxf3 2. Sf6#

1. ... Lg4 2. Sc7#

1. ... dxc3 2. Td1#

1. ... d3 2. Txd3#

1. ... Txb3 2. Le6#

1. ... Dxb4 2. Te5#

1. ... Dxb3 2. Le6#

1. ... Dxb5 2. Se7#

1. ... axb4 2. Te5#

1. ... Txf4 2. Tc5#

1. ... Tg4 2. Sc7#

1. ... Txh3 2. Sc7#

1. ... Lxf3 2. Sf6#

1. ... Lg4 2. Sc7#

1. ... dxc3 2. Td1#

1. ... d3 2. Txd3#

1. ... Txb3 2. Le6#

1. ... Dxb4 2. Te5#

1. ... Dxb3 2. Le6#

1. ... Dxb5 2. Se7#

1. ... axb4 2. Te5#

25 - P1381966

Probleemblad 1993

2. ehrende Erwähnung h#

151. Thematurnier

(5+8)

h#2

shy Bosma

2 Lösungen

**Hans Uitenbroek**Probleemblad 1993

2. ehrende Erwähnung h#

151. Thematurnier

(5+8)

h#2

shy Bosma

2 Lösungen

1) 1. Sxg2 Lh6 2. Se1+ Le2#

2) 1. Sxd3 Lb4 2. Se5+ Tg1#

2) 1. Sxd3 Lb4 2. Se5+ Tg1#

Preisrichter: "This is one of a kind with the 1st HM composition, with so many effects. That the black knight in one solution blocks on e1, but one misses a corresponding block in the other solution (Tg1 covers c1), was my reason for lowering this one place."

AB: This follows an transient early form of Bosma where despite the Bosma condition, the two kings cannot be adjacent. I term this "shy Bosma". Taken on its own terms, this problem appears to be sound as of the 434 solutions found by WinChloe, exactly 432 of these involve touching kings, leaving two solutions which may be taken to form a matching pair, although the WinChloe record for the problem does not mention multiple solutions.

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AB: This follows an transient early form of Bosma where despite the Bosma condition, the two kings cannot be adjacent. I term this "shy Bosma". Taken on its own terms, this problem appears to be sound as of the 434 solutions found by WinChloe, exactly 432 of these involve touching kings, leaving two solutions which may be taken to form a matching pair, although the WinChloe record for the problem does not mention multiple solutions.

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**Keywords:**Bosma (shy), Capture key

**Genre:**h#, Fairies

**Computer test:**C? WinChloe 3.51 finds 2 solutions, but maybe there would be other mates under shy Bosma where e.g. a flight is attacked by wK and two other units. So this problem is not proven to be sound.

**FEN:**5B2/8/8/b7/3p1n2/1r1B1KP1/2p3R1/n2k3b

**Input:**A.Buchanan, 2020-11-16

**Last update:**Alfred Pfeiffer, 2020-11-20 more...

26 - P1381967

Probleemblad 1993

1. ehrende Erwähnung h#

151. Thematurnier

(4+10) cooked

h#2

shy Bosma

2 Lösungen

**Oswaldo Faria**Probleemblad 1993

1. ehrende Erwähnung h#

151. Thematurnier

(4+10) cooked

h#2

shy Bosma

2 Lösungen

The intended solutions are:

1) 1. Sa4+ Sc4 (Se4?) 2. Kd2 Sb2#

2) 1. La5+ Se4 (Sc4?) 2. Kd2 Sf2#

with dual elimination

Cook: 1. La5+ Se4 2. Sd4 Sxc5#

1. ... Sf7 2. Sd4 Se5#

1. ... Sb7 2. Sd4 Sxc5#

1. ... Sc4 2. Sd4 Se5#

1) 1. Sa4+ Sc4 (Se4?) 2. Kd2 Sb2#

2) 1. La5+ Se4 (Sc4?) 2. Kd2 Sf2#

with dual elimination

Cook: 1. La5+ Se4 2. Sd4 Sxc5#

1. ... Sf7 2. Sd4 Se5#

1. ... Sb7 2. Sd4 Sxc5#

1. ... Sc4 2. Sd4 Se5#

Preisrichter: "A good problem. Here in both solutions the 3x + occurs with reduction from 3- to 2x +. And it appears to the white king that the 3x + with the mate move is not undone."

AB: This follows an transient early form of Bosma where despite the Bosma condition, the two kings cannot be adjacent. I term this "shy Bosma". Taken on its own terms, this problem is unsound as of the 22 solutions found by WinChloe, only 16 of these involve touching kings, leaving 6 non-matching solutions. The WinChloe record for the problem does not mention multiple solutions.

Correction at P1382067

comment

AB: This follows an transient early form of Bosma where despite the Bosma condition, the two kings cannot be adjacent. I term this "shy Bosma". Taken on its own terms, this problem is unsound as of the 22 solutions found by WinChloe, only 16 of these involve touching kings, leaving 6 non-matching solutions. The WinChloe record for the problem does not mention multiple solutions.

Correction at P1382067

comment

**Keywords:**Bosma (shy), Superseded by (P1382067)

**Genre:**h#, Fairies

**Computer test:**C- WinChloe 3.51 finds 6 shy solutions, but maybe there would be other mates under shy Bosma where e.g. a flight is attacked by wK and two other units. So there may still be other solutions to be found.

**FEN:**8/3p3p/1K1N3r/2n4p/1b6/3k1n2/2R1R3/1r4q1

**Input:**A.Buchanan, 2020-11-16

**Last update:**Alfred Pfeiffer, 2020-11-20 more...

1. Lh2! (Zugzwang)

1. ... Ta4 2. Txb5#

1. ... Tbxc4+ 2. Kd4#

1. cxb5? droht 2. Kd4#

1. ... Tbe4 2. b6#

1. ... Txb5 2. Txb5#

1. ... Tbd4!

1. ... Ta4 2. Txb5#

1. ... Tbxc4+ 2. Kd4#

1. cxb5? droht 2. Kd4#

1. ... Tbe4 2. b6#

1. ... Txb5 2. Txb5#

1. ... Tbd4!

28 - P1382047

PDB Website 18/11/2020

RK, version AB

(5+8) C+

#2

Bosma

**Robert Ketzscher**

Andrew BuchananAndrew Buchanan

PDB Website 18/11/2020

RK, version AB

(5+8) C+

#2

Bosma

1. Sxd6? droht 2. Sb5#

1. ... cxd6 2. Lxd6#

aber 1. ... e1=D,T,L,S! 2. Sb5+ e2!

1. Sxe3? droht 2. Sc2#

1. ... fxe3 2. Txe3#

aber 1. ... d4 2. Sc2+ d5!

1. Sd4! droht 2. Sb5,Sc2#

1. ... e1=S 2. Sb5#

1. ... c6 2. Sc2#

1. ... cxd6 2. Lxd6#

aber 1. ... e1=D,T,L,S! 2. Sb5+ e2!

1. Sxe3? droht 2. Sc2#

1. ... fxe3 2. Txe3#

aber 1. ... d4 2. Sc2+ d5!

1. Sd4! droht 2. Sb5,Sc2#

1. ... e1=S 2. Sb5#

1. ... c6 2. Sc2#

AB: Version of original at P1381882 which was sound, no mean feat prior to computer verification of this tricky condition. However sLd5 & wBc4 can be replaced by cleaner sBd5, which renders most of the thematic play unique, unblocks c4 as a potential checking square for wS, and is generally more harmonious between the two halves of the problem. I don't know what potential concern led to the Ld5 choice, but WinChloe indicates the simpler approach is sound. The dual threat is thematic.

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**Keywords:**Bosma, under-promotion (s)

**Genre:**2#, Fairies

**Computer test:**C+ WinChloe v3.51

**FEN:**5B2/2p5/3p4/3p1N2/p4p2/k3p2R/4p3/KR6

**Input:**A.Buchanan, 2020-11-18

**Last update:**A.Buchanan, 2020-12-09 more...

29 - P1382067

PDB Website 18/11/2020

OF, correction AB

(4+7) C+

h#2

Bosma

2 solutions

**Oswaldo Faria**

Andrew BuchananAndrew Buchanan

PDB Website 18/11/2020

OF, correction AB

(4+7) C+

h#2

Bosma

2 solutions

1) 1. Sa6+ Sc6 2. Kd4 Sb4#

2) 1. Sd7+ Se6 2. Kd4 Sf4#

2) 1. Sd7+ Se6 2. Kd4 Sf4#

AB: Corrects original at P1381967, which was unsound and shy, with 14 units. The correction is sound and unshy, with only 11 units - but it's so much easier with an engine to check. The kings are not particularly close, but sLb6 in P1381967 leaks an attack onto c7, and wK can ascend that wick. By shifting the roles of the Black officers, everything can work out. The w2 move remains common in both solutions, leading to a mate pattern invented by Sam Loyd, impossible to reach legally in orthodox chess.

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30 - P1382079

Probleemblad 1993

1. Lob h#

151. Thematurnier

(4+10)

h#3

shy Bosma

**Johann Christoffel van Gool**

Henk le GrandHenk le Grand

Probleemblad 1993

1. Lob h#

151. Thematurnier

(4+10)

h#3

shy Bosma

1. Td3 Ke3 Dc3 Kd4 Tg4 e5#

The current WinChloe results are consistent with this problem being sound under shy Bosma: hurray!

The current WinChloe results are consistent with this problem being sound under shy Bosma: hurray!

Preisrichter: "This problem is very interesting, but it only has one solution. But it is funny to see that the white king of all pieces which closes the black queen line to e5!"

more ...

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more ...

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**Keywords:**Bosma (shy)

**Genre:**h#, Fairies

**Computer test:**WinChloe v3.51 finds 13995 Bosma solutions. However, in 13994 of these, the kings bump against one another. There might be another mate achievable only by dint of the kings *not* being adjacent, where Bosma condition would normally allow them to be closer.

**FEN:**8/2nbp3/3k1b1R/3Pq3/4PK2/5rr1/1p4n1/8

**Input:**A.Buchanan, 2020-11-18

**Last update:**A.Buchanan, 2020-11-19 more...

intended solution:

1. Th3+ Kd3 2. Th4+ Ke4 3. Th5+ Kf5 4. Lh7 Lf8#

WinChloe finds an enormous number of h#4.0 solutions with non-shy Bosma. I stopped the program running. Maybe someone else can complete the run, and identify if there are any shy solutions apart from the intended one?

1. Th3+ Kd3 2. Th4+ Ke4 3. Th5+ Kf5 4. Lh7 Lf8#

WinChloe finds an enormous number of h#4.0 solutions with non-shy Bosma. I stopped the program running. Maybe someone else can complete the run, and identify if there are any shy solutions apart from the intended one?

**Keywords:**Bosma (shy), Checking key, Aristocrat

**Genre:**h#, Fairies

**Computer test:**WinChloe finds an enormous number of h#4.0 non-shy Bosma, before I stopped the program running. Maybe someone else can complete the run, and identify if there are any shy solutions apart from the intended one.

**FEN:**8/4B3/6bk/8/8/8/2K4r/1q6

**Input:**A.Buchanan, 2020-11-19

**Last update:**Alfred Pfeiffer, 2020-11-27 more...

Intended solution

1. De5 droht 2. De8#

1. ... Sd7+ 2. Kf7+ and if Sxe5+ 3. g7+ Kh7 4. g8=D#

Cook: 1. Sxb6+! Lb8 2. Txb8+ Txb8 3. Kf7#

1. Ke6+!,Kf5+! Tg7 2. Sxb6+ Lb8 3. Txb8#

1. De5 droht 2. De8#

1. ... Sd7+ 2. Kf7+ and if Sxe5+ 3. g7+ Kh7 4. g8=D#

Cook: 1. Sxb6+! Lb8 2. Txb8+ Txb8 3. Kf7#

1. Ke6+!,Kf5+! Tg7 2. Sxb6+ Lb8 3. Txb8#

AB: WinChloe reports three short solutions, also another full length cook and various duals in the intended solution. In any case, I feel the problem is anticipated by Dr Robert Norman's study P1377131, and is at best a version

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**Keywords:**Bosma (shy), anticipated (P1377131)

**Genre:**3#, Fairies

**Computer test:**C- WinChloe v3.51

**FEN:**R1N4k/br6/1n3KP1/6Pb/8/8/8/Q7

**Input:**A.Buchanan, 2020-11-19

**Last update:**A.Buchanan, 2020-11-19 more...

33 - P1388716

PDB Website 18/04/2021

after Isaak S. Birbrager

(7+1)

Take back a move and then #1

Bosma

**Andrew Buchanan**PDB Website 18/04/2021

after Isaak S. Birbrager

(7+1)

Take back a move and then #1

Bosma

See P1377353

It would be nice to find a position with more Bosma tries than 4 (2021-04-18)

comment

**Mario Richter**: In what sense does "Bosma" help here? (e.g. why does it exclude Solutions like R: Tf4-f1, dann 1. De2#?) (2021-04-18)**A.Buchanan**: 1. Tf4? 2. De2+? Kc4!It would be nice to find a position with more Bosma tries than 4 (2021-04-18)

**A.Buchanan**: WinChloe finds zero solutions for ser-#2, which is promising. (2021-04-19)comment

**Keywords:**Help retractor, Aristocrat, Castling as mating move, Castling in the retro play, Bosma, Rex solus (s)

**Genre:**Retro, Fairies

**FEN:**8/8/1N2Q3/7B/N7/3k4/8/R4RK1

**Input:**A.Buchanan, 2021-04-18

**Last update:**Erich Bartel, 2021-04-18 more...

1. Kd3! Tb4xc4 2. Ke4#!

https://matplus.net/start.php?px=1678037195&app=forum&act=posts&tid=2508&fid=gen&page=0

https://www.reddit.com/r/chess/comments/jk3h61/between_1985_and_1992_the_fide_laws_of_chess/

https://matplus.net/start.php?px=1678037195&app=forum&act=posts&tid=2508&fid=gen&page=0

https://www.reddit.com/r/chess/comments/jk3h61/between_1985_and_1992_the_fide_laws_of_chess/

Show statistic for complete result. Show search result faster by using ids.

https://pdb.dieschwalbe.de/search.jsp?expression=k%3D%27bosma%27

The problems of this query have been registered by the following contributors:

James Malcom (13)A.Buchanan (21)

https://www.ecforum.org.uk/viewtopic.php?f=2&t=10842&p=245798#p245798

https://chess.stackexchange.com/questions/29990/when-was-it-possible-for-a-players-king-to-be-attacked-by-3-of-the-opponents-p/29992#29992

http://www.arves.org/arves/images/PDF/EG_PDF/eg95.pdf

An old Dutch site: http://www.caissa-amsterdam.nl/caissa-post/om-de-tanden-op-stuk-te-bijten/#respond

An obituary of the author's father: https://www.keverelchess.com/exmouth/pioneers/3199/

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