Puzzle of the week #86

Level: 
3-Bishop
Chess Diagram: 

-R------
--------
--------
-----k--
-----p--
-p-----r
----K---
--------

The morning after the admission testing is always calm and sunny. It is good to play chess, isn't it? It is a bit like being a scientist working to discover a new theory that will bring a lot of good to people. He looks at what he knows over and over again, trying different ways to come up with new ideas the same way we look at our puzzles. Sometimes inspiration comes in the most unexpected way; for Archimedes (approx. 287 BC - 212 BC) - the famous Greek inventor - it once came while taking a bath. It is the moment forever remembered in history when he exclamed "Eureka!" meaning "I found it!" while running on the street naked.
Today puzzle might be one of those moments for you. It is the end of the game between 2 Grand Masters: Bronstein - Smislow, Groningen Holland 1946 Black is very much in control with his extra 2 pawns and winning the game seems just a matter of time. He decided to use the skewer and moved 1... b2 Your task:
a) Was this a good idea? Please provide a line showing how Black wins (if you think it was a good idea), or how White saves the game (if you think it was not a good idea);
b) Explain your solution.
Total available points for this puzzle is 15. The answers will be published next week together with puzzle #87.

Puzzle #85 solution:
Surprisingly I did not get very good answers this time. The most important reason is everyone chose poor play for Black in his task to still save the game. If you are behind it is time to challenge yourself and come up with ideas and tricks; anyone can play when they are in front. Here is one partial good answer I got from James: James explanation:
b) "White here is up a Knight and has a extra passed pawn and must try to promote it while Black will do his best to stop it. Winning is just around the corner for White and he should quickly finish the game." Indeed White should focus on using the positional advantage on the Queen side to win the game. Once you have established this, coming up with the right moves (meaning best play for both sides) is not that hard. After:
41.Na6 Ra7 42.Nc5+ Kd6 43.a6 ... Black's pieces (Rook and Bishop) will be blocked defending against the "a6" pawn. Please note the position of "Nc5" on a dark square, something his Bishop cannot attack. Black is strategically completely lost here and winning is quite easy. The nice trick there comes if Black choses to attack as he did in the game and this had to be accounted for at the beginning:
41.Na6 Rc4 42.Nc5+ Kd6 43.a6 Rxd4?? 44.Rb6+! Kxc5 or 44... Bc6 45.Rxc6! Kxc6 46.a7 ... and neither the King or the Rook can stop the pawn from promoting. The White Knight blocks them both!
45.a7 Bc6 46.Rxc6 ... and this is an easy win. In the game Black managed to stop the pawn but lost all his other pawns on the King side; after that he resigned.

Correct solutions:
Andy Q - 15 points
Owen - 12 points
James - 10 points
Rick - 5 points

STANDINGS

Andy Q - 160 points
Rick - 140 points
Jeremy - 88 points
Joshua - 71 points
Owen - 60 points
Wilson - 54 points
James - 53 points
Alex Ge - 51 points
Karl - 39 points
Katerina, Andy Y - 20 points
Marcus - 19 points
Nathaniel - 18 points

Comment: 

Rook + 2 pawns vs. lone Rook