unshouldering

 

Black to move. White wins

8/8/4K3/8/4pk2/8/8/R7 b - - 1 1

White wins, no matter who has to move. If the white king was in the area with the circles, it would be a draw, no matter who has the move. If the white king was adjacent to a square with a circle, white would win if he has the move, but it would be a draw if black had to move.

g6, g7, h6, h7 form a curious bulge. That is caused by the fact that the black king shoulders away the white king. The fact that white wins when his king is on h5 (and he has the move), has to do with that white can expel the black king from his blockade with a check.

So a new technique annex transferable concept is created:

A rook can chase away a shouldering king with a check.