04-02-2013, 09:11 PM
George Murphy Wrote:From abstract to practical. The WPs on d2 and f2 form a barrier. This plus the stipulation that the WK cannot step from a W square to a Black means that the WB must end up on e4 in order to conform with Keith's stipulated choice between e3 and e4. If the WB were forced to settle on e3 to defeat one or other threat, then a capture by d2 or f2 would have been equally possible. So, the WB must be forced to choose e4 - not e3. That means that the Black Rook originally from a8 must be threatening mate from e4. (The BQ is confined to Black squares.) The WK cannot step onto a white square (d1/f1) to evade the check. So, the WB is forced to capture on e4.
So, that's the solution. But, a Black Rook could equally threaten mate from e6, when a WB capturing it would stalemate the Black King. That seems to me to be an improvement, but I'm not setting the puzzle. Note, too, that another stipulation could have been set. Black could have been required to help White impose a selfstalemate. For this purpose, the move ...e6, met by B x e6 would have served just as well.
Wonder if it might have been possible to create a position in which the two sides (W & B) could have been required to effect a reflex-selfstalemate? That's when the side with the move is required to effect a stalemate if such is possible.
Sorry, lost me there completely George. Where did the rook and mate threats appear from? =|