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--- chess:programming:rating:estimate_chess_engine_playing_strength:nolot [2021/12/08 13:16] – created peter
+++ chess:programming:rating:estimate_chess_engine_playing_strength:nolot [2021/12/08 13:42] (current) – peter
@@ Line 31: / Line 31: @@
 ===== Problem 3 =====
 <code>
@@ Line 51: / Line 50: @@
 </code>
+----
+===== Problem 5 =====
+<code>
+r2qrb1k/1p1b2p1/p2ppn1p/8/3NP3/1BN5/PPP3QP/1K3RR1 w - - 0 1
+.e5!! dxe5 22.Ne4! Nh5 23.Qg6!? (stronger is 23.Qg4!! Nf4 24.Nf3 Qc7 25.Nh4 +- ) 23...exd4? (23...Nf4 24.Rxf4! exf4 25.Nf3! Qb6 26.Rg5!! covering b5 and threatening Nf6 or Ne5-f7+) 24.Ng5 1-0
+</code>
 ----
+===== Problem 6 =====
+<code>
+rnbqk2r/1p3ppp/p7/1NpPp3/QPP1P1n1/P4N2/4KbPP/R1B2B1R b kq - 0 1
+... axb5!! offers an exchange to keep the white queen out of play. 14.Qxa8 Bd4 15.Nxd4 cxd4 16.Qxb8 0-0! 17.Ke1 Qh4 18.g3 Qf6 19.Bf4 g5? (Ivanchuk found 19...d3! during post-game analysis.) 20.Rc1 exf4 21.Qxf4 Qd4 22.Rd1 bxc4 23.e5 Qc3+ 24.Rd2 Re8 25.Bxd3 cxd3 -+
+</code>
+----
+===== Problem 7 =====
+<code>
+r1bk2r/2R2ppp/p3p3/1b2P2q/4QP2/4N3/1B4PP/3R2K1 w k - 0 1
+.Rxd8+!! Rxd8 (1...Kxd8 2.Ra7! Qe2 3.Qd4+ Ke8 4.h3 Qe1+ 5.Kh2 Rd8 6.Qc5 Qh4 7.Ba3 Rd7 8.Ra8+ Rd8 9.g3 1-0) 2.Ba3 Qe2 3.h3! Bd7 (better but still losing was 3...Qe1+ 4.Kh2 Qa5 5.Re7+ Kf8 6.Rd7+ Kg8 7.Bb4 Rxd7 8.Bxa5 +-) 4.Nf5! Qd1+ 5.Kh2 f6 6.exf6 1-0
+</code>
+----
+===== Problem 8 =====
+<code>
+r3rbk1/ppq2ppp/2b1pB2/8/6Q1/1P1B3P/P1P2PP1/R2R2K1 w - - 0 24
+.Bxh7+!! is natural, but Black has some defensive resources. 24...Kxh7 25.Qh5+ Kg8 26.Rd4! gxf6 27.Rg4+ Bg7 28.Qh6 Kf8 29.Rxg7! Rac8 (computers prefer 29...Be4 which also loses after 30.Rg4+ Ke7 31.Rxe4 Rad8 32.c4 Qa5 33.Rae1 +-) 30.Qh7 b5 31.Rd1 Bd5 32.c4 bxc4 33.bxc4 1-0.
+</code>
+----
+===== Problem 9 =====
+<code>
+r4r1k/4bppb/2n1p2p/p1n1P3/1p1p1BNP/3P1NP1/qP2QPB1/2RR2K1 w - - 0 1
+.Ng5!! hxg5 2.hxg5! (with the idea of 3. Nf6!!) and now:
+A. 2...Rac8 3.Nf6!!
+A1. 3...gxf6 which loses if white play precisely: 4.gxf6 and now:
+A1a. 4...Nxd3? 5.Rxd3 Bxd3? 6.Qh5+ is mate in 4.
+A1b. 4...Re8 5.Rxc5! (5.Qh5!? Kg8 6.Rxc5! Bg6! 7.Qh4 Bxc5 8.Be4 Ne7 9.Kg2! is winning as well.) 5...Bxc5 6.Qh5 with the idea 7.Be4 and White is winning.
+A1c. 4...Bg6 5.Bxc6 Bxf6 (6...Rxc6 6.fxe7 Re8 7.Bg5 f5 8.Bf6+ Kg8 9.Qd2 is winning) 7.Rxc5 Be7 8.Rcc1 and White is better.
+A2. 3...Nb8 4.Bd5!! (to block d5 so White can play Kg2 without having to deal with ...Qd5+; 4.Qh5!? Bxf6 5.gxf6 Nbd7 (5...gxf6 6.Rxc5! Rxc5 7.Be4 f5 8.Kg2! Rg8 9.Rh1 Rg7 10.Bh6 Nd7 11.Bxg7+ Kxg7 12.Qxh7+ Kf8 13.Qh6+ Ke8 14.Qg5 is winning.) 6.Bb7 Nxb7 7.Rxc8 Rxc8 8.Qxf7 Rg8 9.Qxd7 with advantage for White.) 4...exd5 (4...Qxd5 5.Nxd5 exd5 6.Kg2! should win as well.) 5.Kg2! Bxf6 6.Rh1! Bg5 7.Qh5 Bh6 8.Bxh6 with mate to follow.
+B. 2...Rfc8 3.Nf6!!
+B1. 3...gxf6 4.exf6! (4.gxf6 Nxd3 (4...Bf8 5.Rxc5! Bxc5 6.Qh5 Kg8 7.Be4 Bxe4 8.dxe4 wins for White.) 5.Rxd3 Bxd3 6.Qxd3 Nxe5! 7.Rxc8+ Rxc8 8.Bxe5 Qa1+ is unclear, probably a draw.) and now:
+B1a. 4...Bf8? 5.Rxc5! Bxc5 6.Qh5 Kg8 7.Be4 Bxe4 8.dxe4 is winning for White, e.g. 8...Qa4 9.Rc1 Ne7 10.fxe7 Qe8 11.Kg2! f6 12.Qh6.
+B1b. 4...Nxd3 5. Rxd3 Bf8! (6...Bxd3 6. Qxd3 wins for White.) 6.Rxc6 (6.Bxc6!? Rxc6 7.Rxc6 Qd5 8.Rc7 is better for White.) 6...Rxc6 7.Bxc6 Rd8 8.Rd1 is also favorable for White.
+B2. 3...Bg6 is probably Black's best try:
+B2a. 4.Bxc6 gxf6 5.exf6 Bf8! 6.Bxa8 Rxa8 7.Rc4 and Black seems to hold.
+B2b. 4.Qg4 gxf6 5.gxf6 Nxd3 (5...Bf8? 6.Qh3+ Kg8 7.Bh6! is winning) 6.Rxd3 Bf8 7.Rdd1 is unclear.
+Pierre Nolot seems to have repudiated this problem.
+Nxh6 much better than Ng5:  Nxh6 gxh6 Bxh6 Qd5 Bg5 Ra7 Bxe7 Rxe7 Ng5 Qxe5 Qh5 f5 Bxc6 Qd6 Qh6 Kg8 Bb5 Rb8 Be8 Nd7 Bf7+ Rxf7 Nxf7 Qf8 Qxf8+ Nxf8 Ne5 Bg6 Nxg6 Nxg6 Rc6 Kf7 Re1 Nf8 Ra6 Rb7 Rxa5 Kf6 f4 Nd7 Rc1 Kf7 Rc4 Nf6 Kf2 Rb6 Rxd4 Kg7 Ra8 Kg6 Kf3 Nd5 Ke2 Kh5 Rc4 Nf6 Kf3 Kg6 Rd8 Kh5 d4 Kg6 Rh8 Ng4 Rhc8 b3 R8c7 Nf6 R4c6
+</code>
+----
+===== Problem 10 =====
+<code>
+r1b2rk1/1p1nbppp/pq1p4/3B4/P2NP3/2N1p3/1PP3PP/R2Q1R1K w - - 0 15
+.Rxf7!! Rxf7 16.Bxf7 Kxf7 17.Qh5+ Kg8 16.Qe8+ Bf8 19.Nd5 Qxd4 20.Ne7+ Kh8 21.Rf1 Qf6 22.Rxf6 and white won on move 29.
+</code>
+----
+===== Problem 11 =====
+<code>
+r1b3k1/p2p1nP1/2pqr1Rp/1p2p2P/2B1PnQ1/1P6/P1PP4/1K4R1 w - - 0 1
+Neishtadt's "Leçons de tactique" gives: "1.Rxh6!! the g pawn will be helped by the h pawn 1...Nxh6 (1...Rxh6 2.Bxf7+ Kxf7 3.g8Q+) 2.Qg5 Nf7 3.Qd8+!! Nxd8 4.h6 and there is nothing to prevent h6-h7+ 1-0"
+But 4...Qd4!! 5.h7+ Kf7 6.g8Q+ Ke7 7.h8Q Kd6 8.Rg7 Qxd2!! 9.Qxd8 Qd1+! (if 9...Kc5? 10.Rxd7 Bxd7 11.Qxa8 Kb4 12.Qh1! and White wins. Not 12.Qxa7? Qe1+ 13.Kb2 Qc3+ with perpetual check.) 10.Kb2 Qd4+ 11.Ka3 Qc5+ 12.b4 Qe3+ 13.Bd3 Qc1+ 14.Kb3 Qb1+ 15.Kc3 Qe1+ 1/2 as White cannot escape the black checks.
+</code>
+----
 ===== References =====
 https://en.wikipedia.org/wiki/Nolot