In order to win an ending without pawns, it is usually not enough to be a minor piece up. It follows that the material balance in the diagram should lead to a draw, but White's problem is that his rook is under attack, and after it moves Black will play ...Nac3+ winning the knight on a1. Two extra pieces is certainly enough to win, unless there is an immediate draw for some reason. Find white's move that leads to a draw.(Please read the annotations in the end)

Hint: The clue is the last sentence in the question. White has to find a way to lose his knight in such a way as to set up a tactical defense. Remember than a king and two knights cannot win against a lone king, so if the rooks were exchanged...

uhhh.... if black take the rook with his white loses badly... isn't a puzzle supposed to show an objective achieved without any possibility of failing in your goal? this puzzle falls apart with black knowing even rudimentary chess.

A very beautiful study. By whom is it again?

If black takes white's rook with his own rook, it's stalemate.

Very nice.

Please read the annotaions.

Thanks tonydal.

If white took blacks rook with his, it's stalemate