The Rule Of The Square EXPLAINED! The square rule states that the king can catch the pawn if it can step into the square on its next move. If that's not the case, the pawn can reach the promotion square before the king gets to it. The black king cannot step into the square in the example above, so White is free to run with their pawn to promote. After this video, you will understand exactly hoe to apply the rule of the square to your games! Thx For Watching! Enjoy!