Puzzle of the week #128

Level: 
5-Queen
Chess Diagram: 

---rkb-r
pp---pp-
--p-b--p
----P-q-
--BQ----
--N-----
PPP---PP
-K-R---R

We saw in the previous puzzle (best answer for it follows below) how important it is to pay attention during the entire game, all the way until your opponent shakes your hand. Paying attention and correctly evaluating a position will always lead you in the right direction. This truth brings us to today's puzzle: middlegame position where one side (Black) has left its King in the center. It is White's turn to move and it is a decisive moment. What should White do:
a) Exchange Queens and one Rook on "d8" to make sure the Black King stays in the center and use its better development to attack in the center;
b) Sacrifice Bc4 with 17.Qxa7 ... in order to destroy Black's pawn group on the Queenside.

For both options you need to provide: analysis, conclusion and the best line you can put together.
Total available points for this puzzle is 20. The answers will be published next week together with puzzle #129.

Puzzle #127 solution:
Owen's answer follows:
"Material:
White: 1xKing; 1xQueen; 2xRooks; 2xBishops; 1xKnight; 5xpawns
Black: 1xKing; 1xQueen; 2xRook; 1xBishop; 2xKnight; 6xpawns
Conclusion: Black is up by a pawn.
King Safety:
White: King is under attack and in big danger of being mated.
Black: The King is not under attack yet, but it is not very safe either. White's Rook on h1, Pawn on g5, Bishop on e5 and the Queen have enough power to attack the Black King. Black King is trapped on one side by his Rook on f8 and by his f7 pawn.
Conclusion: Both Kings are unsafe but in this situation Black King is in safer position than White King:
Position:
White: is under attack and in the danger to be wiped out or even mated. In addition to it Black has the next move. Black has the advantage of a pawn. Also White's Bf1 and Ng1 are blocked and useless. Thus White is down more than just by a pawn. White needs to defend his own King. However it has a chance to put a lot of pressure on the Black King if given a tempo through the Rook on h1 pawn on g5, Bishop on e5 and Queen on c2.
Black: is up by a pawn. It has tempo. All pieces are developed. White King is almost trapped. The weakest link is the pawn on h6. It provides very weak defense for the Black King. The King seems to be trapped a little by own Rook on f8 and pawn f7. Moving pawn to f6 gives the  Black King the way of escape, but it also allows white to keep the tempo if white will be given a chance to attack.
Conclusion: Black position is much better than white.

A) Choose the most probable continuation in the game:
If Black plays:
20... Qd5 
Then White will win the game after
21.Qh7+ Kxh7 22.Rxh6+ Kg8 23.Rh8# 1-0

If Black plays:
20... Qxg5
It seems like the game has becoming more even and White even have a chance to have a slight advantage after:
21.f4 Qg3 22.Rxh6 Nc1+ 23.Qxc1 f6 24.Rh3 Bb3+ 25.Ka1 Qxh3 26.Nxh3 Rxa3+ 27.Qxa3 bxa3 28.Rxd2 fxe5
If Black plays:
20... Nc1+
Black should have no problem to win the game:
21.Qxc1 c3 22.Bxc3 bxc3 23.gxh6 Qd5+ 24.Ka1 Nb3+ 25.Kb1 Qf5+ 26.Qc2 Nd2+ 27.Rxd2 cxd2 28.e4 Bxc2+ 29.Kxc2 Qg5 with advantage Black

B) My best line is the one starting with 20... Nc1+

C) What do you think happened in the game?
This is a very good question. Let me analyze it now. I do not know who played this match. Knowing if it happened between Grand masters or juniors or even in our club would be quite helpful for guess purposes only.
Assumption #1
20... Qd5 is a blunder; if it happened, then it is a win for white
20... Qxg5 looks like Black chickened out with White g5 and Rook on h1 and was not sure of their own attack. Win for white or draw
20... Nxc1+ is the best move for Black and only logical. Win for black
Because it is a puzzle, I am guessing black lost or had a draw. Otherwise there is nothing special to talk about.
Assumption #2
Black has advantage and should win without a problem. Because this is a puzzle I am assuming Black did not win it. Thus now it is between the draw and win for white. There is a chance for a draw after 20... Qxg5 but also it should give white advantage
20... Qd5 gives white win for sure.
Assumption #3
1. If it was played between GMs then 20... Qxg5 and eventually white won
2. If it was played by anybody else 20... Qd5 and of course white mated black
Conclusion: White won"

Excellent answer! Owen deserves an extra 5 points for the effort and inspiration. It is interesting to note this was one of the round 6 games between FM Hambleton (CAN) - GM Friedel (USA) at the Canadian Open 2010. We can only assume Black was overconfident when he casually played 20... Qd5?? and lost!

Correct solutions:
Owen - 25+5 points
Karl - 23 points
Jeffrey, Rick - 20 points
Frank - 15 points
Alex - 5 points

STANDINGS

Owen - 75 points
Karl - 62 points
Frank - 40 points
Rick - 39 points
Jeffrey - 33 points
Edwin - 19 points
Alex - 14 points

Comment: 

The art of attack (1)