[Retros] Solidarity chess (=SC)

Noam Elkies elkies at math.harvard.edu
Wed Dec 19 20:40:16 EST 2012

Eric Angelini <Eric.Angelini at kntv.be> writes:

> I am right (!), no possible conflict [...]

> I know that I am not allowed to put delibarately my King in check --

> but how does this affect the chess game where the only rule is: -

> you win the game by capturing the opponent's King, period?

No real difference as long as you're concerned only with orthodox play
(wins stay wins, "mate in n" becomes "win in n+1", etc.). But in
help-play (including "proof games") it is crucial that the cooperation
between White and Black does not extend to Black ignore White's putting
his King in check, or indeed put Black's own King in check; and in
selfmates it is perhaps even more crucial that Black is forced only
to reach a checkmate position, not to actually capture the King --
and along the way Black's options are usually restricted by the
obligation not to move into check or remain in check, even if
Black would prefer to do so. So unless your SC variant also
replaces win-by-checkmate by win-by-K-capture, it is still a
natural question whether in SC proof game one is allowed to
deliberately allow an solidarity-breaking move en route to the
desired diagram.


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