A king and a rook are on opposite corners of an 8x8 chessboard. The king is trying to avoid being checked by the rook. Normally the rook would check the king in one move but this rook is restricted - his moves are limited to up to two spaces, that also applies to his ability to make the check.

Can the king avoid check indefinitely? If not, how long can he last?

(In reply to Open question by Steve Herman)

I believe the check is achieved on the Rook's 7th move. With the King trapped in the 2x2 corner, depending on the King's position, the Rook's 5th move is 1 or 2 spaces toward the King or the mission accomplishing check. The best the King may do is move to the corner after the Rook's 5th move, thus extending his survival. Yet, the Rook effectively traps the King in the corner. If this corner in chess notation is H1, the 6th move of the Rook is to G3 or F2 (depending on the former position). The King can then no longer position himself to avoid a check after the Rook's next move.  

Posted by Dej Mar on 2016-01-11 13:40:48