Puzzle of the week #226

Submitted by Eugen on Mon, 04/29/2013 - 21:27

The g7-square hot spot (2)

Chess Diagram
[Event "Puzzle #226"][Date "2013.04.29"][Result "1-0"][SetUp "1"][FEN "2r1nrk1/5ppp/p4b2/1pqNpP2/4B3/P2P2RQ/1P1BKN1P/8 w - - 0 1"]
This is an imbalance position from the middlegame. Your tasks:
a) decide what makes the position imbalanced
b) analyse the position and propose the best plans for both sides
c) White to move - propose the best variation for White leading to a win

Total available points for this puzzle is 25. The answers will be published next week together with puzzle #227.

Puzzle #225 solution:
Calin Dragomirescu - VE Demian, Timisoara 1977. Both players were in grade 7 at the time. 3 out of 4 conditions for the sacrifice on g7 are met, but missing the 4th one makes the sacrifice wrong:
1. The g7-pawn has not moved - Yes
2. The attacker must use at least one Rook - Yes
3. Any piece such as Knight, Bishop, Rook or Queen can be sacrificed on the g7-square - Yes
4. In general the usual setup is a Rook on the g-file attacking the g7-square and a Bishop or Queen attacking the same spot along the diagonal a1-h8 - NO
White's battery "Qd2 + Be3" is setup on th wrong diagonal and that gives Black enough time to not only successfully defend its position, but also to counter-attack and win. Here is the continuation from the game:
[Event "Puzzle #225"][Date "2013.04.21"][Result "0-1"]1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nf6 5.Nxf6+ exf6 6.Be3 Be7 7.Nf3 O-O 8.Bd3 Bg4 9.h3 Bxf3 10.gxf3 Nd7 11.Rg1 Qc7 12.Qd2 Rfd8 13.O-O-O c5 {Solution} 14.Rxg7+ Kxg7 15.Rg1+ Kh8 16.Bh6 Rg8 17.Rxg8+ Rxg8 18.Qe3 Nf8 19.Qe4 Ng6 20.h4 Qh2 21.Qxb7 Qxh4 22.Be3 cxd4 {Black won at move 30}

Correct solutions:
James - 17 points
Daniel - 15 points
Jerry, Leo - 10 points
Aditya - 5 points

Daniel - 219 points
James - 216 points
Leo - 156 points
Justin - 116 points
Derrick, Richard - 89 points
Jerry - 52 points
Aditya - 38 points
Alex - 7 points