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MatPlus.Net Forum Promenade A pawn remaining as a pawn upon promotion

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### A pawn remaining as a pawn upon promotion

In a general chess forum, someone asked: what if it were legal for a P to "promote" to a P - are there situations where such a move would be the best? It turns out this was answered back in the 19th century when the rules were in dispute - see https://en.wikipedia.org/wiki/Promotion_(chess)#1862_British_Chess_Association_rule for a position where a P=P move is the only way to draw via stalemate.

Here's my attempt at the task. Can it be improved, e.g. done in miniature?

(= 2+6 )

1.e8(P)! and Black cannot stop the stalemate, while 1.e8(Q) would lose to 1...g3 2.Qg6 g2+ 3.Qxg2+ fxg2.

A P=P as the only move that WINS is much harder to set up, of course, but it turns out to be possible:

(= 9+10 )

Black threatens queen mates on a8 and f7. 1.exf8(Q/R)=. 1.exf8(B) Se7+ 2.S/Bxe7=. 1.exf8(S) Sxf6+ 2.gxf6=. 1.e8(Q) Qxf7+ 2.Qxf7 Se7+ 3.Q/Sxe7=. Engine analysis indicates that other white moves would actually lose. Therefore 1.exf8(P)!! avoids all stalemates and after 1...Sxf6+ 2.gxf6 Kh7, White is still a piece ahead and so wins the ending easily.

Does anyone know of precursors, or can anyone construct alternative positions?

Of course there's this classic:

Sam Loyd
American Chess Magazine
dec. 1898

(= 9+3 )

±3

1.cxd8 pawn

and not:
1.cxd8Q/R? stalemate
1.cxd8B?,Bf5+!
1.cxd8S?,Bc6+!

Thanks, Jan! I should've guessed that Sam Loyd had done something wacky like this. And I didn't even consider it could be done as a directmate!

I don't know about predecessors, but here is a miniature:

(= 2+5 )

Draw

1.f8Q? Sf4! wins as there are no checks, but 1.f8P! draws.

I also wondered if it is possible to make a study where both sides choose not to promote. That turned out to be easy by adding two pieces to your study:

(= 10+11 )

BTM, Win

1...gxh1Q 2.exf8Q wins easily since 2...Qxe4+ 3.dxe4 is not stalemate. But on 1...gxh1P!? White has to play 2.exf8P!

Both of your settings look good to me, Geir. In the second, it's remarkable that such a small adjustment results in two pairs of matched promotions. P=P moves by both sides is pretty funny!

I really should not post after refereeing a chessmatch the day before;
I first overlooked Black is in check. :-)

But since with Geir it's personal (hey, the guy has a mere 200
ELOs more than me) I have to offer a setting with 6 pieces :-)

(= 2+4 )

1.c8Q? Qf3!

Hauke

Nice one, Hauke. I like how 1...Qh8 mate is stopped by the key.

(= 2+4 )

a) diagram
b) c3->c4

a) c8=P=
(1.c8=Q? Bc4! wins)

b) c8=Q=
(1.c8=P? R2c3!)
1.c8=Q! Rb4 2.Qb8! R2c4 3.Qe8! Re4 4.Qc6+! Kd1 5.Kxa2!=

a step to auw?

Nice find! When I searched the matrix I didn't have the guts
to place another rook inmid the botanics :-)

This is just brilliant!

Since we are screwing with the rules anyway...
(= 3+3 )

#1, a) Dia: 1.gxh8=bR b) -Sg8, 1.g8=bS
...this joke is way old. Can you motivate a promotion to
black bishop (yes, but I didn't flesh out the details)
or even queen? In a study? (Note in a) we
can promote to bP too, but we break one rule at a time :-)

Hauke

(= 4+4 )

And a last one. This is an old study of mine from our club zine
INSELSCHACH, which just extends a well-known trick.
1.Ke6! h5 2.gxh5 g4 3.Kf5 g3 4.Kg6 g2 5.Kh6 =
Clearly 5...g1Q,R stalemates, g1B is a well known fortress
and even the most dangerous g1S is drawn after 8...Sxa2 9.Kd4
since a2 soon will be forced with another fortress.
The winning move, clearly and obviously, is g1K,
feel free to find a more economic setting :-)

Hey Hauke, here's some answers to your questions in post 11 here that you posed two whole years ago!

I'm not sure of a WINNING promotion to a black queen, but I remember this study given on Chess Stack Exchange with a promotion to a black queen that leads to a draw. Here is that question:https://chess.stackexchange.com/questions/13322/is-there-any-position-where-not-promotingillegally-would-be-the-best-move

Matt Bengtson, Chess Braintwisters (Burt Hochberg), No. 103. White=

(= 4+9 )

1. g8=Black Queen! Qg7+ 2. fxg7 c2 3. g8=Q c1=Q 4. Qxf7+ Kd8 5. Qe8+ Kc7 6. Qc8+ Kb6 7. Qc6+ Ka5 8. Qb5+ Kxb5

As for motivation to promote to a black bishop, I found one myself: to avoid stalemating the opponent. Here's my own little composition based on that idea. Feel free to find the obvious solution.

A mate in one with it is impossible. It also cannot be done it two moves, otherwise white has a mate in one in the starting position.

White To Mate In 3

(= 8+4 )

While the same idea could be done minus the horse and a few pawns, I want the solution to be the ONLY winning move that White has. This means that white shouldn't be able to move a piece to let the black king out, nor should they be able to force black to make a capture. A black knight could be promoted to, but that would prevent a mate a 3. At best it would be mate in 5 then.

Plenty of winning positions can be made for a promotion to a black pawn, horse, knight, or bishop. Drrawing positions for all of those plus the queen as shown above, are also possible. But the Holy Grail yet to be found is a case of WINNNG by promoting to a black queen. Could this be done?

Another idea is where both sides simultaneously promote to an enemy piece, similar to the earlier post here that has double non-promoting pawn. There are winning and drawing for all combinations of piece promotions. The promotion must be the best move of course. Could something be made for this?

Henceforth I propose the Reverse Basbon. I deem this a direct mate in four problem. One side makes a key move, and then the other side promotes, illegally, to an enemy piece, and then the enemy's best move is to the do the same. For all four types of promotions.

Most of us here on Matplus wouldn't be able to solve that, if it could be doing at, but it's just a fun idea.

Another idea of mine is the Extended Reveri Babson. It's the same idea, but instead it's a direct mate in 5 with a non-promomting pawn move thrown in as well

I'm not going to include promotions to a king in those of course. Does anyone know of a king promotion puzzle? I have seen one before but I can't find it at the moment. Perhaps a simultaneous illegal king promotion could be made.

There are a lot of problems with strange promotions:
https://pdb.dieschwalbe.de/search.jsp?expression=K=%27Joke%20promotion%27

In this list you'll find P1160804 with a #2 with promotion to black bishop.

Thanks, but the link doesn't work. It says "Please specify a search criterion."

PDB is known for glitches...

(= 4+2 )

Camille Moriau, 97 150 Schachkuriositäten 1910

Thanks Hauke. What is the stipulation here though? I had a few questions, so I'm not sure which one it answers to.

"Capriccio", as it seems :-) (#2 technically.)
More can only be found in the original...

Ah, see the trick here now in that position. White promotes to a black bishop, forcing black to use that bishop and deprive the black king of his only escape square. Then white announces checkmate with their dark-squared bishop on their very next move. Much more economical than mine! And I am wrong that a #2 with is it not possible! I'll try to cook up something like this for promotion to a black queen and pawn!

I also finally found some illegal king promotions from a puzzle featured in this ChessBase article: https://en.chessbase.com/post/study-of-the-month-2018-07

I will quote the relevant portion of the story:

"An alien came to Earth, learning chess. His teacher Yuri Dorogov won a lot of material and the diagrammed position emerged."

(= 7+3 )

"Dorogov decided to mate in two with 1.Kc2, but having not taught the promotion rules thoroughly backfired now, as the cunning alien replied with 1...h1=K!"

(= 7+3 )

"Indeed, now 2.Bd4 is mate for one king but stalemate for the other, so it is only a draw. Dorogov, however, exploited his mistake to his advantage and played the incredible move 2.a8=bK (see diagram), moving his pawn to a8 and promoting into a black king!

The alien had only one move 2...Kb8 and Dorogov won after all with 3.h7 Ka8 4.h8Q###, a triple checkmate."

(= 6+4 )

So this features not only a king promotion, but a further illegal king promotion of one pawn color into the piece of the other color! Amazing!

Here's my own constrcution with dual illegal enemy king promotion. It's an easy h=2 with WTM.

(= 12+12 )

A dual promotion to one's own colored king for a draw is possible, but I'll do that sometime later.