Puzzle of the week #127

Chess Diagram: 


Arguably the most spectacular games are the result of opposite sides attacks. The deal is very simple: lead your attack faster to the opposing King. This can be done by attacking ony and no intentions to defend unless you have to, or by carefully combining the attacking moves with clever defensive ones to delay or even stop the incoming opposite attack. This week you get to see a real example. White's last move in the above position was 20.hxg5 ... The opposite wing attack situation is quite obvious, so your tasks are:
a) Choose the most probable continuation in the game (10 points):
20... Nc1+ Black decides to continue the attack because it has enough attackers to be successful;
20... Qxg5 Black decides to delay White's attack first since his attack cannot be stopped anyway;
20... Qd5 Black decides to bring into the attack the strongest weapon since White's attack seems slower.
b) Come up with the best line in the continuation of your choice; explain your answer (10 points).
c) What do you think happened in the game? (5 points)

Total available points for this puzzle is 25. The answers will be published next week together with puzzle #128.

Puzzle #126 solution:
It was the end of the game between Tiviakov - Arbakov, 1989. The most complete answer is the one sent by Owen. Please note that his very good analysis helped him find the solution. It goes like this:
White: 1x King 1x Queen and 3x Pawns.
Black: 1x King 1x Queen and 3x Pawns.
Material is even.
King Safety:
White: White's King is opened but his only danger is the Black Queen. If Black gets a tempo he can only check the White King, but not mate him.
Black: Black's King is behind his own pawn. The White f6-pawn covers the e7 and g7 squares, so the Black King can't escape there. Black is attacked by the White Queen and he can get mated.
White's King is safer.
White: White has a good attack on the Black King. The only defender in White's way is the Black Queen. White needs to get rid of the Black Queen with a distraction.
Black: Black should try to advance his pawn and transform into a second Queen, to help his own Queen in the attack against the White King; if that doesn't work, try to protect his own King.
Option 1:
1.a3! Qg4 2.Qb8+ Qc8 3.Qxc8#
Option 2:
1.a3! Qxb3 2.Qc5+ Kg8 3.Qg5+ Kf8 4.Qg7+ Ke8 5.Qg8#
Option 3:
1.a3! Qd2 2.Qb8+ Qd8 3.Qxd8#
Option 4:
1.a3! Qxa3 2.Qb8#"

Without a good analysis the best you can do is guess the correct answer. Thank you Owen! In reality Black resigned right after 1.a3!! ... 1-0

Correct solutions:
Owen - 20 points
Edwin, Rick, Karl - 19 points
Frank - 10 points
Alex, Jeffrey - 5 points


Owen - 45 points
Karl - 39 points
Frank - 25 points
Edwin, Rick - 19 points
Jeffrey - 13 points
Alex - 9 points


Opposite sides attack (2)