Author: Howard Exner
Date: 20:56:26 03/09/98
Go up one level in this thread
On March 09, 1998 at 11:31:02, Amir Ban wrote: > >This is the last installment in the ECM errata report. I've been busy >with other matters recently, so this took some time. I did not review >yet Howard's and Bruce's comments to the latest batch, but, on >experience, they are reliable. > >I hope now Don and others can take on this and compile the ECM98 suite. > > >No. 810 (Rxg6+): > >Is the intent here: 1.Rxg6+ hxg6 2.Nxg6 fxg6 3.Qc2 ? If so 3...Ne5 >4.dxe5 Ne4. > >Recommend: Drop it. The book move given as best is Nxg6, not Rxg6. Must be an error in the epd file. [FEN "2rqr1k1/pb2bp1p/1pn1pnpB/4N3/3P4/P1N3R1/1P3PPP/RB1Q2K1 w - - 0 1"] 1. Nxg6 hxg6 2. Bxg6 fxg6 3. Qb1 1-0 > > >No. 818 (Rxg6+): > >Rxg6+ evaluates to around +4. I find e4, threatening Rxg6+. I evaluate >it higher at +5.6. > >Recommend: Add e4. Yes as Bruce has confirmed also. > > >No. 824 (Nxf3): > >Rxf3 also works, and evaluates about the same (+2.8). > >Recommend: Add Rxf3. I agree with adding Nxf3 > > >No. 827 (Rxf3): > >I find 1...Rxf3 2.gxf3 Qh4 3.Re1 and white's mate threat makes this line >doubtful. Junior prefers a quiet Qh4. > >Recommend: Investigate. [FEN "1r1q1r1k/2p3pp/1p1bQ3/p7/1PP5/Pn3B2/1B3PPP/R4RK1 b - - 0 1"] 1... Rxf3 2. gxf3 Qh4 3. Be5 Nd4 4. Bg3 Qxg3+ 5. hxg3 Nxe6 This is the book line but it is not a big plus. The book does not consider the better defense you found of 3.Re1. I think this one could be dropped. > > >No. 833 (Nf6+): > >I can't find a convincing line after Nf6+ gxf6, but the quiet Qg3 seems >to win (+122). > >Recommend: Drop it. [FEN "rqbn1rk1/1p3ppp/p3p3/8/4NP2/8/PPP1BQPP/1K1R3R w - - 0 1"] 1. Nf6+ gxf6 2. Qg3+ Kh8 3. Qh4 Kg7 4. Rd3 Re8 5. Rh3 h5 6. Bxh5 Rg8 7. Rg3+ Kf8 8. Qxf6 Rxg3 9. Qxd8+ Kg7 10. hxg3 This is the book and it seems to confirm what Bruce found. It is a long line. Many combinations often contain a "Rook Lift" theme as in 4.Rd3 in the above line. Looks like one to keep. > > >No. 841 (Nxe6): > >I find this line 1.Nxe6 Qxe6 2.Nd5 Kd8 3. Qd2 Qe5, which is not good >enough. > >Recommend: Investigate. [FEN "r1b1kb1r/1p1n1ppp/p2ppn2/6BB/2qNP3/2N5/PPP2PPP/R2Q1RK1 w - - 0 1"] 1. Nxe6 Qxe6 2. Nd5 Kd8 3. Bg4 Qe5 4. f4 Qxe4 5. Bxd7 Bxd7 6. Nxf6 This looks good. Black can try the greedy 4. ... Qxb2 but that also looks futile. Keep it. > > >No. 846 (Rxe3): > >I'm not convinced: 1...Rxe3 2.fxe3 Nxe3 3.Qd2 Bxd4 4.Ndc5 is not worth >Black's trouble. > >Recommend: Investigate. [FEN "3qr1k1/rp3pbp/2p3p1/3p1b2/N1nP4/P2NP3/1PQ2PPP/1BRR2K1 b - - 0 1"] 1... Rxe3 2. fxe3 Nxe3 3. Qd2 Nxd1 4. Qxd1 Bxd4+ 5. Kh1 Be3 6. Rc3 d4 7. Rc5 Bxd3 8. Bxd3 b5 9. Rxc6 bxa4 This line looks good for black but the game would need to contiue to prove the win. The book line only considers 3.Qb3 which is not as good as Qd2. Bruce, is this similar to what you discovered? > > >No. 852 (Rxb2): > >Nd3+ is even better (Rxd3 is forced. If Bxd3 Bxc3). > >Recommend: Add Nd3+ [FEN "1r3rk1/5pbp/p2Pp1p1/q1n3P1/2p2P1P/2N1Q2R/PP6/1BKR4 b - - 0 1"] 1... Rxb2 2. Kxb2 Na4+ 3. Kc2 Nxc3 Both this book line and your Nd3 look equally strong. > > >No. 856 (Rf1): > >Black needs to draw. It's probably right, but too deep for me. I see >1... Rxf1 2.Rxf1 Rxf1 3.Qe2 Bg1+ 3.Kh1 Rc1 but it's not over yet. > >Recommend: Investigate. [FEN "5rk1/5rp1/p2qb3/R2Np2Q/3bP2B/7P/P5PK/1R6 b - - 0 1"] 1... Rf1 2. Rxf1 Rxf1 3. Ne7+ Qxe7 4. Bxe7 Bg1+ 5. Kg3 Bf2+ 6. Kf3 Bb6+ 7. Ke2 Bc4+ 8. Kd2 Bxa5 This is the longer of the two drawing lines from the book. > > >No. 858 (Bxh2+): > >Hard to make a ruling on this: 1...Bxh2+ 2.Kxh2 Qh4+ 3.Kg1 fxg2 4.Kxg2 >Rxf2+ 5.Qxf2 Qg4+ black can probably get a perpetual here, but to prove >it is not easy. > >Recommend: Investigate. [FEN "3r1rk1/p3q1pp/2Rb4/3P4/8/1P2Qp2/PB3PPP/3R2K1 b - - 0 1"] 1... Bxh2+ 2. Kxh2 Qh4+ 3. Kg1 fxg2 4. Kxg2 Rxf2+ 5. Qxf2 Qg4+ 6. Qg3 Qe2+ 7. Kh3 Qh5 so says the book. This line draws but there is a longer line with 6.Kh2 which might prove more difficult to draw. Too deep for me to conclude anything. Bob Hyatt, march down to the Cray office and borrow the super computer for the weekend :) > > >No. 860 (Qd8+): > >This is bad. The assignment "white to draw" assumes that black is >winning, which is not the case. I find Qd3 +155. If 1...bxa4 2.Bxf7+! >wins. > >Recommend: Drop it. Agree > > >No. 864 (Nf5): > >(Black to draw) This is probably bad: 1...Nf5 2.Qxd5 Ng3+ 3.Kh2 (I think >even Kg1 is good enough to win) Ng1+ 4. Kg1 Qh2+ 5.Kxf1 Qf4+ 6.Ke2 Qxc1 >7.Qxf7+ black is lost. > >Recommend: Drop it. Agree, the book line plays Rc4? instead of the better Re1. > > I concur with your remaining conclusions. >No. 865 (Nxg5): > >Nxg5 draws, right, but who wants to draw here ? I get a plus score for >a5. > >Recommend: Drop it. > > >No. 866 (Rg8+): > >The idea is that Kh5 loses and Kh6 is a perpetual after Ne5, but what >about Kh4 ? I get this breathtaking line: 1...Kh4 2. Qe2 Bb5 3.f3 Bxd3 >4.Qe1+ g3! 5.Rg4+ Qxg4 6.fxg4 Be4! and I count this as good for black. > >Recommend: Drop it. > > >No. 867 (Rxh5): > >Why does white want to draw here ? > >Recommend: Drop it. > > >No. 875 (Qg1+): > >Why does black want to draw ? I want to play 1...Bxc5 2.Rxc5 when 2...f5 >or 2...Qf6 are to black's advantage. In any case, if black insists on a >draw, he can play 2...Qg1+ now, so this is at least a cook. > >Recommend: Drop it. > > >No. 879 (Rd2): > >This is unclear. First, Rd2 does draw (2. Qxd2 Nxf2+ 3.Kg1 Nxe4, or >2.Qc3 Rxb2 etc.), but then so does Nxf2+ by transposition. Second, I >play Nxf2+ with intent of maintaining a black advantage, though this may >be wrong. My line is: 1...Nxf2+ Kg1 2.Nd3 Bxd3 3.Qxd3 Qg6+ 4.Kf2 Qg2+ >5.Ke3 Qxb2 unclear. > >Recommend: Drop it. > > >Amir
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