[Retros] The problemist May 2008

[Joost de Heer]

Noam Elkies schreef:

> Alain> Concerning the following problem, i have a proof game leading to

> Alain> the position where castlings rights allow two mates in two.

> 

> Alain> 4k2r/1p2ppsb/1p2p2Q/bP2S1S1/2P2Pp1/2P2Pp1/2PR2P1/R3K3

> 

> Joost> White can't castle either if b6 came from c7.

> 

> Note too that the forward play here is not as transparent as is usual

> for such problems.  The try 1 Rad1? (2 Rd8#) fails not because of

> 1...0-0? (2 Qxh7#) but because 1...Bxc3 pins Rd2; thus White's reason

> for preferring 1.0-0-0 is to get out of the prospective pin, not

> to prove 1...0-0 is impossible as one typically expects in such problems.

> The try 1 Sexf7? (same threat and answer to 1 0-0) fails to 1...Bd3!.

> 1 Sgxf7 (same threat) deals with both Bishop defenses (1...Bxc3/Bd3

> 2 Ra8/Qxh8#) but not with 1...0-0.  So the choice between 1 0-0-0

> and 1 Sgxf7 depends on the history of the diagram.


As far as I can see it, black can't castle anyway (his pawns captured 3 
times, including the h-pawn, which couldn't have captured since the 
other white pawns need 4 captures, so it promoted on h8 and then either 
got captured or it's still on the board as a promoted piece).

Joost