Author: Ed Schröder
Date: 22:13:50 09/25/99
Go up one level in this thread
On September 25, 1999 at 18:44:17, Peter McKenzie wrote: >In a game on ICC Beadle (LambChop) reached the following interesting position: > >2kr1b1r/ppp4p/1q4p1/3p1p1b/3N4/2PQPPP1/PP1N2P1/R4RK1 w - - 0 17 > >Tactics: > >Here LambChop blundered with Nxf5, it needs an 8 ply search to avoid Nxf5. The >key variation being Nxf5 gxf5 Qxf5+ Kb8 Qxh5 Qxe3+ Rf2 Bc5 Rf1 Qxd2. This is a >10 ply variation, but we have a couple of checks in there so the check extension >sallows it to be seen in 8 ply. > >My q-srch prunes out captures that look bad, so Qxd2 is pruned as the simple >algorithm I use thinks d2 is protected by the R on f2 :-( I guess if my pruning >algorithm in q-srch was smarter then I'd see this line one ply earlier. I'd >also see it earlier if I just looked at all captures in q-srch... > >How many ply do other programs need to avoid Nxf5 ? I know that crafty needs 8 >ply too... > > >Positional: > >I was slightly surprised when Bob Hyatt said he thought white was doing badly >anyway (crafty agreed). I personally think that white is doing fine, I actually >prefer white's position. > >Here is how I see the position: >White has 2 knights vs two bishops, so white should try to keep the position >somewhat closed. Currently the knights are quite well posted, while the Bh5 is >quite bad although the Bf8 is potentially very good but currently not doing >much. > >White's pawn structure is weakened, but black isn't currently in a position to >take advantage of this. White will probably play f4 eventually, leaving holes >on e4 and g4 but this doesn't look too bad for white as black doesn't have a >knight to sink in there. Also, the white knights cover those squares quite >well, and after f4 the Bh5 is really locked out. > >White has a clear and simple plan of advancing on the queenside. I think black >should try to open the position and infiltrate the dark squares, but its not >clear to me how to achieve this. > >I think white should play 1.b4 which is in harmony with the plan of advancing on >the queenside, it also dissuades c5 (thereby keeping the strong knight on d4) >and has the added bonus of possibly threatening Nxf5. I wouldn't worry about >Nxf5 too much though, as even if it wins a pawn the variations look very open >and dangerous for white. > >After 1.b4, ...c5 looks poor. Simply 2.bxc5 followed by 3.Rab1 with good >initiative for white. > >Another line is 1.b4 Bd6 2.f4 Rhe8 3.a4 threatening a5 Qa6 b5 trapping the black >queen :-) > >Maybe something like Qf6 is best for black? The idea being to play g5 >eventually. Pretty slow though. > >So there you have it, the opinion of someone used to be 2300 Fide but these days >struggles to maintain a 2000 ICC bullet rating :-) :-) Here is what Rebel makes of it, it fails low at 7 plies score -2.xx and then switches to a4 and later to b4. Below is the log. Ed ------------------------------------------------ Thinking.... +---+---+---+---+---+---+---+---+ am Nxf5 - NXF5.EPD 8 | | | *K| *R| | *B| | *R| +---+---+---+---+---+---+---+---+ 00:00:00 00:00:00 7 | *p| *p| *p| | | | | *p| +---+---+---+---+---+---+---+---+ 6 | | *Q| | | | | *p| | Time infinite +---+---+---+---+---+---+---+---+ Hash 60 Mb 5 | | | | *p| | *p| | *B| Engine Rebel Century +---+---+---+---+---+---+---+---+ Personality Rebel Century 4 | | | | N | | | | | anti-GM Off +---+---+---+---+---+---+---+---+ System Tiger Off 3 | | | p | Q | p | p | p | | Combination Off +---+---+---+---+---+---+---+---+ Style Normal 2 | p | p | | N | | | p | | Strength Strongest +---+---+---+---+---+---+---+---+ Search Normal Search 1 | R | | | | | R | K | | +---+---+---+---+---+---+---+---+ a b c d e f g h 2kr1b1r/ppp4p/1q4p1/3p1p1b/3N4/2PQPPP1/PP1N2P1/R4RK1 w - - [Event "?"] [Site "? "] [Date "1999.09.26"] [Round "?"] [White "am Nxf5"] [Black "NXF5.EPD"] [Result "*"] [WhiteElo "?"] [BlackElo "?"] [FEN "2kr1b1r/ppp4p/1q4p1/3p1p1b/3N4/2PQPPP1/PP1N2P1/R4RK1 w - - 0 1"] 1.* 00:00:00 1.00 -3.54 1.Ne6 Qxe6 00:00:00 1.01 -0.36 1.Nxf5 Qxb2 00:00:00 2.00 -0.09 1.Nxf5 Qxb2 2.Rfb1 Qa3 3.Nb3 00:00:00 3.00 -0.09 1.Nxf5 Qxb2 2.Rfb1 Qa3 3.Nb3 00:00:00 4.00 -0.09 1.Nxf5 Qxb2 2.Rfb1 Qa3 3.Nb3 00:00:00 5.00 -0.11 1.Nxf5 Bxf3 2.Rxf3 gxf5 3.Nb3 Bg7 4.Qxf5+ Kb8 (0) 00:00:01 6.00 -0.17 1.Nxf5 Qxb2 2.Rab1 Qa3 3.g4 Bxg4 4.fxg4 gxf5 5.Qxf5+ Kb8 (1) 00:00:04 7.00 -2.64 1.Nxf5 gxf5 2.g4 Be8 3.Qxf5+ Rd7 4.Rae1 Qxb2 (3) 00:00:11 7.01 -0.48 1.a4 Bh6 2.Rae1 Rhf8 3.b4 Qd6 4.Ne2 00:00:28 8.00 -0.50 1.a4 Bh6 2.Rae1 Rhf8 3.b4 Qd6 4.Kh2 Rfe8 (23) 00:00:35 8.03 -0.47 1.b4 Bd6 2.Kh2 Rhf8 3.a4 Be5 4.a5 Qd6 5.f4 Bg7 (29) >LambChop gives white as +0.4 after 9ply, and wants to play a4. > >So what do other people/programs think? >cheers, >Peter
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