Puzzle of the week #152

Submitted by eugen on Sat, 02/19/2011 - 17:53

The edge of a Knife

Level
3-Bishop
Chess Diagram
[Event "Puzzle #152"][Date "2011.02.19"][Result "1-0"][SetUp "1"][FEN "r4rk1/1p5q/p2p1p1Q/4p2N/2Pp4/8/PP5P/5R1K w - - 0 1"]
Most of the times when players are of equal stregth and that is GM level, we see long games with "all in" attacks and stubborn defences. The result stays on the edge of a knife until peace is made or one of the sides falters and all is decided. Our current position falls into this category: 2 GMs are facing each other, White has sacrificed an exchange and some for an "all in" attack and Black has defended extremely well.
It is White's turn to move and you should decide which of the following options is the best:
a) Black has successfuly defended and after 32.Nxf6+ Rxf6 33.Qxf6 Qe4+ both sides will make peace with a perpetual check on the White King
b) If we played so long, why not continue the attack to whatever end?
c) White resigned since after the Queens get exchanged those 4 central Black pawns will overpower White

Please explain your choice and provide the best line you can think of for each one of them. Total available points for this puzzle is 15. The answers will be published next week together with puzzle #153.

Puzzle #151 solution:
Joanne Foote - Pawnislander, Internet game, Jan 2011. This puzzle was tougher than expected. It takes a lot more chess knowledge to analyse a position properly and come up with a plan for both sides when there's no clear solution in front of us. Surprisingly the best answers came from Derrick and Jeffrey:
a) Jeffrey - position analysis:
White:
1. Rook on an open file
2. Should try to keep the position closed or try to exchange at least one Bishop
Black:
1. Up a pawn
2. Pawn majority on the Q-side
3. Rd5 has restricted movement
4. Bg7 guards f6 under attack and with a possible fork
5. Has the Bs pair
CONCLUSION:
White would want to trade pieces.
Black would want to keep the Bs pair and use the pawn majority to create a passed pawn

b) Derrick - White lost the game because it lets her Bishop off his post! The Bishop's purpose was to destroy the base of the pawn chain, but Black simply advances his pawn by minimizing White moves. Immediately the pawns on a5-b4 and c5-d4 come in effect by taking out the Rook with pawn moves and bxc3 captures the Rook for sure. The Black pawns can work together to create a Queen and deliver a back rank checkmate.
c) Derrick - White should counter attack; see solution:
[Event "Puzzle #151"][Date "2011.02.14"][Result "1-0"][SetUp "1"][FEN "6k1/5pb1/6pp/p1pr1b2/1p1pNB2/7P/PPP1RPP1/6K1 w - - 0 27"]{In the game} 27.Bc7 (27.Bxh6 Bxh6? (27...Bxe4 28.Bxg7 Bxc2 29.Bxd4 Rxd4 30.Rxc2) (27...c4 28.Bxg7 Kxg7 {White got his pawn back but black is still better}) 28.Nf6+ {White wins}) 27...a4 28.Bb6 c4 29.Ng3 d3 30.cxd3 cxd3 31.Rd2 Bc3 {Black is winning}

Correct solutions:
Jeffrey, Derrick - 20 points
Kevin, Leo - 18 points
Ziyao, Alex - 15 points
James, Philip - 13 points
Leroy, Harmony - 10 points

Standings:
Ziyao - 112 points
Harmony - 85 points
Alex - 79 points
James - 77 points
Philip - 67 points
Jeffrey, Leo - 52 points
Derrick - 43 points
Leroy - 38 points
Frank - 33 points
Kevin - 29 point
Danny - 19 points
Karl - 13 points