Puzzle of the week #122

Level: 
4-Rook
Chess Diagram: 

---Q----
-----pp-
------k-
----R---
--------
b-----K-
--------
--------

Let's try another puzzle with a clear cut finish to it. The advantage is more overwhelming than in the previous one and the result is not in doubt. However there's always possible to challenge yourself and one challenge you should always do your best to overcome in your games is to win all games where you have advantage as soon as possible. It does not only give you a chance to relax for the next game, but also helps you develop the habit of playing good, solid chess. Last but not least any correct play creates a sentiment of joy and happiness.
In the above position the challenge is simple:
a) White to move and mate in 3 moves

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #123.

Puzzle #121 solution:
This was a study created by Carvajal in 1889. Most of you have found it really easy. Karl explains why:
"I find it very easy to visualize the mate and the moves in my head. I got my answer by process of elimination: if this doesn't work and the
Black King get stalemated, then the other move will probably work. Also keeping Black to only one or two possible moves is key; pretty much all the
moves are unavoidable for black...
1.Kc1 a3 (only move)
2.Nc2+ Ka2 (forced)
3.Nd4 Ka1 (only move)
4.Kc2 Ka2 (zugzwang: 4... a2 results in 5.Nb3#)
5.Ne2 Ka1 (only move)
6.Nc1 a2 (forced)
7.Nb3#
The main idea, I think, is that White can't let the Black King out, and the only place to checkmate it is for the Black King to be on a1. The Knight checkmating move must be on b3 or c2, and also c2 is the best place for the White King to be, so I found a Knight maneuver that fulfills all those criteria."

Very nice explanation!

Correct solutions:
Andy Y, Rick, Edwin, Owen, Karl, Frank, Jeffrey - 14 points
Nathaniel - 6 points
James - 4 points

STANDINGS

Owen - 412 points
Andy Y - 407 points
Karl - 390 points
Edwin - 355 points
Jeffrey - 303 points
Alex, James - 227 points
Andy Q - 214 points
Humphrey - 180 points
Nathaniel - 150 points
Amir - 103 points
Rick - 72 points
Frank - 65 points
Marko - 10 points

Comment: 

Swiss precision