Author: Jeroen van Dorp
Date: 14:29:02 05/17/00
On rgcc Magnus Carlsson posted the following situation. He let Fritz 6(a) do a blunder check of an ICC game and got a strange result. In this game: Sleeper1 (1291) - MagnusCarlsson (1373) [B50] ICC 2 12 Internet Chess Club, 14.05.2000 [Fritz 6] 1.e4 c5 2.Nf3 d6 3.Bc4 e6 4.d3 a6 5.Nc3 g6 last book move 6.a3 Bg7 7.Bd2 Ne7 8.b4 b5 9.Bb3 Qc7? [-1.38 Fritz 6: 9...Nbc6= -0.19/8 ] 10.Rb1 cxb4 11.Ne2 bxa3 12.Qc1 Bb2 13.Qd1 a5 14.0-0 0-0-+ [-2.25 Fritz 6: 14...b4 15.c3 Nbc6 16.d4 0-0 17.Bh6 Re8 18.c4-+ -1.63/8 ] 15.Qe1 b4 16.Ned4 Nbc6??-+ [-5.34 Fritz 6: 16...Ba6-+ -1.97/7 ] 17.Bc1 Bxd4 18.Nxd4 Nxd4 19.Bc4 Bb7 20.c3 Ndc6 21.cxb4 axb4 22.Bb5 Ba6 23.Bxc6 Nxc6 0-1 Fritz made an amazing analysis, when *only* black was blunderchecked, at move 16. Basically Fritz states black did a bad move (didn't) and suggest a move that is even worse. He classifies 16.Nbc6 with ??, give a -5.34 evaluation, suggests Ba6 with evaluation -2.00, which is of course a worse figure for black. Basically 17.Bc1 is the mistake, as the knight (see diagram and play Bc1) is now attacked twice and defended once. If you let Fritz blundercheck *both* sides, it doesn't happen, and it gives a right assesment. I reproduced Magnus's results, and got the same . Is anyone familiar with the things happening here? The blundercheck was performed at 5 secs/move Thx. This is the relevant position after Nb6: [D]r1b2rk1/2q1np1p/2npp1p1/p7/1p1NP3/pB1P1N2/1bPB1PPP/1R2QRK1 w - - 0 17 This is the "black only" blunder check: 1.e2-e4 c7-c5 2.Ng1-f3 d7-d6 3.Bf1-c4 e7-e6 4.d2-d3 a7-a6 last book move 5.Nb1-c3 g7-g6 6.a2-a3 Bf8-g7 7.Bc1-d2 Ng8-e7 8.b2-b4 b7-b5 9.Bc4-b3 Qd8-c7-+ [-1.50 Fritz 6: 9...Nb8-c6= -0.19/8 ] 10.Ra1-b1 c5xb4 11.Nc3-e2 b4xa3 12.Qd1-c1 Bg7-b2 13.Qc1-d1 a6-a5 14.0-0 0-0-+ [-2.28 Fritz 6: 14...b5-b4 15.Bd2-h6 Bc8-b7 16.Bb3-a2 Nb8-d7 17.Ne2-d4 Ra8-c8 18.Bh6-g7 Rh8-g8-+ -1.63/9 ] 15.Qd1-e1 b5-b4 16.Ne2-d4 Nb8-c6??-+ [-5.34 Fritz 6: 16...Bc8-a6 17.Bd2-h6 Rf8-e8 18.Qe1-e3 Nb8-c6 19.c2-c4 b4xc3 20.Bb3-a2 Nc6xd4 21.Nf3xd4-+ -2.00/8 ] 17.Bd2-c1 Bb2xd4 18.Nf3xd4 Nc6xd4 19.Bb3-c4 Bc8-b7 20.c2-c3 Nd4-c6 21.c3xb4 a5xb4 22.Bc4-b5 Bb7-a6 23.Bb5xc6 Ne7xc6 Line This is the "both sides" blunder check: 1.e2-e4 c7-c5 2.Ng1-f3 d7-d6 3.Bf1-c4 e7-e6 4.d2-d3 a7-a6 last book move 5.Nb1-c3 g7-g6± [0.72 Fritz 6: 5...b7-b5 6.Bc4-b3 Ng8-f6 7.0-0 Bf8-e7 8.e4-e5 d6xe5 9.Nf3xe5 0-0 10.Qd1-f3= 0.25/10 ] 6.a2-a3² [0.41 Fritz 6: 6.0-0± 0.72/8 ] 6...Bf8-g7 7.Bc1-d2= [0.12 Fritz 6: 7.d3-d4 b7-b5 8.Bc4-a2 Nb8-c6 9.d4xc5 Bg7xc3+ 10.b2xc3 d6xc5² 0.44/8 ] 7...Ng8-e7 8.b2-b4= [-0.19 Fritz 6: 8.0-0 b7-b5 9.Bc4-b3 0-0 10.Rf1-e1 Bc8-b7 11.Bd2-g5 Nb8-c6= 0.16/8 ] 8...b7-b5 9.Bc4-b3 Qd8-c7 10.Ra1-b1-+ [-1.41 Fritz 6: 10.b4xc5 Qc7xc5 11.d3-d4 Bg7xd4 12.Nf3xd4 Qc5xd4 13.Qd1-f3 Nb8-c6 14.Ra1-d1 Qd4-c5= -0.19/9 ] 10...c5xb4 11.Nc3-e2 b4xa3 12.Qd1-c1 Bg7-b2 13.Qc1-d1 a6-a5 14.0-0 0-0 15.Qd1-e1-+ [-2.25 Fritz 6: 15.c2-c3 Nb8-c6 16.Bd2-h6 Rf8-e8 17.Bh6-c1 Bb2xc1 18.Rb1xc1 b5-b4 19.d3-d4-+ -1.56/8 ] 15...b5-b4 16.Ne2-d416... Nb8-c6 17.Bd2-c1??-+ [-5.34 Fritz 6: 17.Nd4xc6 Ne7xc6 18.Bd2-c1 Bb2-g7 19.Qe1-e3 Bc8-b7 20.d3-d4 Rf8-c8-+ -2.22/10 ]17...Bb2xd4 18.Nf3xd4 Nc6xd4 19.Bb3-c4 Bc8-b7 20.c2-c3 Nd4-c6 21.c3xb4 a5xb4 22.Bc4-b5 Bb7-a6 23.Bb5xc6 Ne7xc6 Jeroen ;-}
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