TheaN: Wednesday 11-19-2008
Nice puzzle here.
White: c5, e4, f2, g3, h3, Nd6, Bg2, Ra1, Re1, Qa2, Kg1
Black: b5, e6, f7, g7, h6, Nf6, Bb7, Ra8, Rd4, Qc7, Kf8
In this seemingly better position for Black, with a lot of pressure on d4 and a Queen en prise, White has a killer move. Black just made a terrible mistake by allowing a strike on a very weak back rank, and in immediate effect will be a piece gain by White.
<29.Qxa8!> pretty much the only puzzle move in this position, but extremely hard to spot in a game. Does White want to put in a lot of time into a seemingly useless sacrifice? This move, although forcing, is followed by one more tactic to finish up, and a lot of players would just stop after Black's second move. I will briefly consider a rejection of this sac, all options under variation A. Simply said, they leads to at least another piece loss.
<29....Ne8 30.Qxe8 1-0>
<29....Qd8 30.Qxd8 Ne8 31.Qxe8 1-0>
<29....Qb8 30.Qxb8 >
<29....Bc8 30.Qxc8 >
<29....Qc8 30.Qxc8 >
<29....Ke7 30.Qxb7 >
Clear enough ;)?
<29....Bxa8 30.Rxa8> now this is more interesting. Suddenly, the same options for Black, although without the Bishop move, seem to arise once again. However...
<30....Ne8 30.Rxe8 1-0>
<30....Qb8/c8/d8 30.RxQ >
<30....Ke7> ...lets skip to the moving King. Now, the simple Qxb7 we had before is gone as the Bishop and Queen are traded and White is now a Queen down for Rook and Bishop. However, in this position the final strike comes.
<31.Ra7!> now this is what most players would miss in a brief examining and drop the variation. A shame, because this ends the game. By the time this is played, Black should notice his Queen is gone due to the fork. Can he reply with something else than QxR to get some initiative? Some simple analysis shows this is impossible.
<31....Kd7/Kd8> defending the Queen. Okay, that seems to win the Rook also with a better positioned King but it does not.
<32.Rxc7 Kxc7 33.Nxb5 > and Black will also lose his Rook, White being a piece and Rook up.
<31....Ne8 32.Nxb5!> and the pin simply remains. Now, Black is forced to play QxR as other it will be gone at the expense of a White Knight only. Take note that after 32.Rxc7?! Nxc7 Black defends b5 and might have some resources in the form of b5, although I doubt it, so Nxb5 is better.
<32....Qxa7 33.Nxa7> and maybe White loses c5, but as the critical b5 pawn is gone, White wraps up with the Bishop easily.
<31....Qd7 32.Rxd7 Kxd7 33.Nxb5 > same as above, although now, in theory, after the immediate Nxb5 Black does not have to take a7 so White is better off doing RxQ himself. As there is no Knight defending b5 after RxQ NxR as there is no Knight to take the Rook back, White gains b5 once again, ending the game.
<31....Qxa7 32.Nc8> so Black might as well take all the tempi he has.
<32....Kd8? 33.Nxa7 > okay, Kd8 is an ill-fated choice: after the logical Nxa7 White threatens forks on b5 and c6, forcing Black to lose b5 once again, and the game.
<32....Rb4 33.Bf1! > picking up the pawn and freeing the Knight, once again.
<32....b4 > and Black has established his best position: the White Knight a bit out of the game, the Bishop rather inactive and a seemingly strong b4 pawn. White wins, but has be slightly careful here. That goes beyond Wednesday, though :).
Time to check.