check extension
Moderators: hgm, Rebel, chrisw
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Re: check extension
Yeah, I considered that, but I did not want to use promoted pieces (so also no Bishops on the same shade).
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Re: check extension
Nice one. Thanks.hgm wrote: ↑Mon Dec 03, 2018 5:42 pm This is a pretty long sequence:
[pgn][Event "Edited game"] [Site "ONTWIKKELLAPTOP"] [Date "2018.12.03"] [Round "-"] [White "-"] [Black "-"] [Result "*"] [FEN "4n2q/Qp4r1/8/4k3/1N6/N1K5/5n2/3R4 w - - 0 1"] [SetUp "1"] 1. Qb8+ Rc7+ 2. Nc4+ Kf4+ 3. Rd4+ Ne4+ * [/pgn]
I am not sure if the requirement that SEE>=0 is realistic in such a sequence: the checks are also evasions, and pruning check evasions seems risky. Without this requirement you could probably make much loger sequences.
Yes, the hope was that SEE >= 0 helps keep such sequences small and rare.
Theory and practice sometimes clash. And when that happens, theory loses. Every single time.
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Re: check extension
Nice mate in 26hgm wrote: ↑Mon Dec 03, 2018 5:42 pm This is a pretty long sequence:
[pgn][Event "Edited game"] [Site "ONTWIKKELLAPTOP"] [Date "2018.12.03"] [Round "-"] [White "-"] [Black "-"] [Result "*"] [FEN "4n2q/Qp4r1/8/4k3/1N6/N1K5/5n2/3R4 w - - 0 1"] [SetUp "1"] 1. Qb8+ Rc7+ 2. Nc4+ Kf4+ 3. Rd4+ Ne4+ * [/pgn]
I am not sure if the requirement that SEE>=0 is realistic in such a sequence: the checks are also evasions, and pruning check evasions seems risky. Without this requirement you could probably make much loger sequences.
[d]4n2q/Qp4r1/8/4k3/1N6/N1K5/5n2/3R4 w - - 0 1
Code: Select all
dep score nodes time (not shown: tbhits knps seldep)
44 #26 1.33G 0:39.89 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8#
43 #26 767.4M 0:23.26 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
42 #26 663.0M 0:20.18 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
41 #26 485.9M 0:14.95 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
40 #26 451.5M 0:13.89 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
39 #26 417.6M 0:12.86 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
38 #26 386.6M 0:11.92 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
37 #26 303.9M 0:09.39 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
36 #26 291.6M 0:09.02 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Rb5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
35 #26 281.2M 0:08.69 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
34 #26 236.4M 0:07.28 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
33 #26 229.6M 0:07.07 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
32 #26 223.6M 0:06.88 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qd5+ Kh7 Qh1+ Rh6 Qxh6+ Kxh6 Nf7+ Kg7 Nxh8 Kxh8 Kd4 Kg7 Rf5 Kg6 Ke5 Kg7 Ke6 Kg6 Re5 Kg7 Rg5+ Kh6 Kf6 Kh7 Rh5+ Kg8 Rh3 Kf8 Rh8
31 #35 214.9M 0:06.61 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Rg3+ Kb2 Rg2 Qxg2 Qxf6 Qxb7+ Kg8 Qc8+ Kf7 Qd7+ Kg8 Qg4+ Kf8 Kc3 Kf7 Nd6+ Qxd6 Qf4+ Kg7 Rg5+ Qg6 Rxg6+ Kxg6 Kd4 Kg7 Qg5+ Kf8 Qf6+ Ke8 Qg6+ Kd7 Qb6 Kc8 Qb5 Kd8
30 #31 159.2M 0:04.86 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Kf8 Qc5+ Kf7 Nd6+ Kxf6 Rf5+ Ke6 Qd5+ Ke7 Qe5+ Kd7 Qxg7+ Qe7 Rf7 Qxf7 Qxf7+ Kxd6 Qxb7 Ke5 Qc6 Kf4 Kd4 Kf5 Qe4+ Kf6 Kd5 Kf7 Ke5 Ke7 Qb7+ Kf8 Qc8+ Kf7
29 #64 136.6M 0:04.17 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Kg8 Qg2+ Qg7 Qxg7+ Kxg7 Ne8+ Kf7 Nxf6 Kf8 Nd5 Kg7 Nb6 Kh8 Re7 Kg8 Nc4 Kf8 Re3 Kg8 Re5
28 +58.79 60.5M 0:01.99 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Kf8 Qc5+ Kf7 Nd6+ Kxf6 Rf5+ Ke6 Qd5+ Ke7 Qe5+ Kd7 Qxg7+ Kxd6 Qd4+ Ke6 Re5+ Kf6 Qxd8+ Kxe5 Qe7+ Kf5 Qxb7 Kg6 Qc6+ Kf5 Qd5+ Kf4 Kd4 Kg3 Qa8 Kg4 Qg2+ Kf4
27 +56.39 45.9M 0:01.58 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Rg3+ Kb2 Rg2 Qxg2 Qxf6 Qxb7+ Kg8 Kb3 Kf8 Qb4+ Kg8 Re8+ Kg7 Qe7+ Qxe7 Rxe7+ Kf6 Re3 Kg5 Kc3
26 +53.14 37.1M 0:01.32 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qh3+ Rh6 Qf5+ Rg6 Qh5+ Rh6 Qxh6+ Kxh6 Nf7+ Kh7 Nxh8 Kxh8 Rb5 Kg7 Rxb7+ Kg6 Rb5 Kf6 Kc3 Kg7 Kd4 Kf6 Re5
25 +53.05 35.3M 0:01.26 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Qg7 Qxg7+ Kxg7 Ne8+ Kf7 Nxf6 Kxf6 Rb5 Ke6 Kc3 Kd6 Kd4 Ke6 Rd5 Kf6 Kc3 Kf7 Rb5 Kg8 Kd4 Kh7 Ke5
24 +53.05 32.1M 0:01.17 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Qg7 Qxg7+ Kxg7 Ne8+ Kf7 Nxf6 Kxf6 Rb5 Ke6 Kc3 Kd6 Kd4 Ke6 Rd5 Kf6 Kc3
23 +52.86 19.3M 0:00.67 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Rg6 Nd6+ Kg7 Nxf6 Rxf6 Qg2+ Kh7 Qxb7+ Qg7 Qxg7+ Kxg7 Ne8+ Kf7 Nxf6 Kxf6 Rb5 Kf7 Kc3 Ke6 Kd4 Kf6 Rh5 Ke6 Re5+ Kd6
22 +19.75 13.5M 0:00.45 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Qh4 Nd6+ Kg6 Qc2+ Ne4 Rxe4 Qxe4 Qxe4+ Kh5 Nf5 Rg1 Qh4+ Kg6 Nfe7+ Kg7 Qd4+ Kh7 Qxg1
21 +17.82 10.3M 0:00.34 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Rg6 Nd6+ Qxd6 Ne4+ Qf6 Nxf6 Rxf6 Rf5 Ke7 Rxf6 Kd8 Kb2 Kd7
20 +13.43 5.92M 0:00.20 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Rg6 Nd6+ Kg8 Ne7+ Kg7 Nxg6 Qh1 Re7+ Kg8 Qxf6 Qg2+ Kb1 Qh1+ Kc2 Qg2+ Kc1
19 +13.06 5.30M 0:00.18 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg8 Ne7+ Kh7 Nxg6 Qg7 Qh4+ Kg8 Ne7+ Kf8 Nef5 Nd5+ Kd4
18 +12.80 5.18M 0:00.18 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg8 Ne7+ Kh7 Nxg6 Qg7 Qh4+ Kg8 Ne7+ Kf8 Nef5 Nd5+ Kd4
17 +12.26 4.18M 0:00.14 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7 Nxf6 Qh1 Re7+ Kh8 Nf7+ Kg7 Ng5+ Kh6 Rh7+ Kxg5 Rxh1 Rxf6 Qg2+ Kf5 Qxb7
16 +11.81 3.92M 0:00.14 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qd8 Nxf6 Kf8 Re8+ Qxe8 Nxe8+ Kxe8 Ne5 Re7 Qf6 Rxe5 Qxe5+ Kd7 Kb4
15 +10.79 3.43M 0:00.12 Nc4+ Ke6 Re1+ Kf7 Qxb7+ Kf6 Qf3+ Kg5 Qg2+ Ng4 Re5+ Kh4 Qh1+ Kg3 Qxh8 Nxe5 Nxe5
14 +10.41 3.11M 0:00.11 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Qh3+ Kb4 Rg6 Nd6+ Kg8 Nxf6+ Rxf6
13 +9.89 3.08M 0:00.11 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2 Qd8 Nxf6
12 +9.75 3.00M 0:00.11 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg8 Ne7+ Kh7
11 +9.37 2.01M 0:00.07 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg3+ Kb2
10 +9.13 1.52M 0:00.05 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf5 Re5+ Kg6 Qg1+ Kf7 Qf2+ Nf6 Nd5 Rg6 Nd6+ Kg7
9 +9.91 531745 0:00.02 Nc4+ Ke6 Re1+ Kf7 Qxb7+ Kf6 Qf3+ Kg5
8 +7.90 102067 0:00.01 Nc4+ Kf5 Qxf2+ Ke6 Qe3+ Kf7 Re1 Nd6 Nxd6+ Kg6 Qe4+ Kf6 Kb3
7 +10.28 71770 0:00.00 Nc4+ Ke6 Re1+ Ne4+ Rxe4+ Kf7 Qxb7+ Kg6 Rg4+ Kh5
6 +8.07 38438 0:00.00 Nc4+ Kf5 Qxf2+ Kg6 Qe3 Rc7+ Kb3 Kf7
5 +8.69 18329 0:00.00 Qxf2 Rc7+ Nc4+ Ke6+ Kb3 Qh3+ Rd3
4 +5.20 16380 0:00.00 Qxf2 Ke6 Kc2 Rc7+ Kb1
3 +5.78 13308 0:00.00 Qxf2 Ke6 Kc2
2 +8.18 9174 0:00.00 Qxf2 Ke6
1 +10.48 5185 0:00.00 Qxf2 Qh3+ Kb2
1 Found 1511 tablebases
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