Winboard Forum

Posted: **17 Oct 2004, 11:35**

This is a slightly updated version, some additional comments have been added, in particular that mate solutions provided by Franz Huber. Positions and solutions have remained unchanged.

3k4/8/4K3/2R5/8/8/8/8 w - - bm Rc1 Rc2 Rc3 Rc4 Rc6; c0 "CCC post"; id "ZPTS.01";
1k6/7R/2K5/8/8/8/8/8 w - - bm Re7 Rf7 Rg7 Rh1 Rh2 Rh3 Rh4 Rh5 Rh6 Rh8+; c0 "CCC post"; id "ZPTS.02";
8/3k4/8/8/3PK3/8/8/8 w - - bm Kd5; c0 "CCC post"; id "ZPTS.03";
2k5/8/1K1P4/8/8/8/8/8 w - - bm Kc6; c0 "white wins"; id "ZPTS.04";
8/8/8/4N3/8/7p/8/5K1k w - - bm Ng4; c0 "white mates"; id "ZPTS.05";
8/8/1p1K4/Pp6/2k1p3/8/1P6/8 w - - bm a6; c0 "Kubbel 1927, 1 ... e3 2 a7 e2 3 a8/Q e1/Q 4 Qd5+ Kb4 5 Qd3!, white wins"; id "ZPTS.06";
8/1p5k/1P1p4/3p4/3Pp2p/2K1P2p/7P/8 w - - bm Kb2; c0 "1 Kb2! Kg8 2 Ka1!!, draw"; id "ZPTS.07";
8/4N3/8/8/8/2b1p3/p1K1P3/k7 w - - bm Nc6; c0 "white mates in 3"; id "ZPTS.08";
8/8/7p/2R5/4pp1K/8/8/3k2b1 w - - bm Rc4; c0 "Kricheli 1986, 1 Rc4! e3 2 Rd4+! Kc2 3 Rxf4 e2 4 Re4 Kd2 5 Rxe2+ Kxe2 6 Kg4!, draw"; id "ZPTS.09";
4KBkr/7p/6PP/4P3/8/3P1p2/8/8 w - - bm g7; c0 "CCC post 27.4.2004 by Gerd Isenberg, white wins"; id "ZPTS.10";
8/p7/1p6/p7/kq1Q4/8/K7/8 w - - bm Qd3; c0 "post in Avler chess forum, mate in 13: 1.Qd3 a6 2.Qd7+ Qb5 3.Qd4+ Qb4 4.Qd3 Qb2+ 5.Kxb2 Kb4 6.Qc3+ Kb5 7.Qc7 Kb4 8.Qc6 a4 9.Kc2 a3 10.Qc3+ Ka4 11.Qc4+ Ka5 12.Kb3 b5 13.Qc7#"; id "ZPTS.11";
8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - bm Re1+; c0 "CCC post by Eduard Nemeth, mate in 7"; id "ZPTS.12";
8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Bd1 Be2; c0 "CCC post by Sune Fischer, Averbakh 1954, white wins: 1.Be2 Be8 [1.-Bg6 2.Bd3 Bh7 3.Bf1 leads to instant zugzwang, be it after 3.-Bg6 4.Bg2 Bf7 5.Bf3 or after 3.-Bg8 4.Be2 Bf7 5.Bf3] 2.Bd3 Bg6 3.Bc2 Bh7 4.Bb3! Bg8 5.Bd1 Bf7 6.Bf3! and so on"; id "ZPTS.13";
6k1/3p4/P2P4/8/5Kp1/1p4Q1/p5p1/b7 w - - bm Qxg2; c0 "Kasparyan 1959, 1 ... Be5+ 2 Kf5! a1/Q 3 a7! Qxa7 4 Kg6! Qa1! 5 Qd5! Kh8 6 Qe4!!, white wins"; id "ZPTS.14";
1r4RK/2n5/7k/8/8/8/8/8 b - - bm Ne8; c0 "Polgar - Kasparov, 1996: mate in 8: 1. ... Ne8 2.Rf8 Kg6 3.Rg8+ Kf7 4.Kh7 Rb5 5.Rf8+ Kxf8 6.Kg6 Rc5 7.Kh6 Kf7 8.Kh7 Rh5#"; id "ZPTS.15";
k2N2K1/8/8/8/5R2/3n4/3p4/8 w - - bm Rf7; c0 "CCC post by Ed Schroeder, Troitzky"; id "ZPTS.16";
8/8/1p1r1k2/p1pPN1p1/P3KnP1/1P6/8/3R4 b - - bm Nxd5; c0 "CCC post 27.4.2004 by Gerd Isenberg"; id "ZPTS.17";
8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - bm Qxh4+; c0 "CCC post 10.9.2004 by Alvaro Begue"; id "ZPTS.18";
n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; c0 "CCC post, mate in 12: 1.Bc7 Qxc8 2.gxf7+ Kh8 3.Be5 Qc5 4.Bb2 Nc7 5.Ba1 a4 6.Bb2 a3 7.Ba1 a2 8.Bb2 a1Q 9.Bxa1 Nd5+ 10.Ke6+ Nc3 11.Bxc3+ Qe5+ 12.Bxe5#"; id "ZPTS.19";
3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; c0 "CCC post, draw, but h5 after Qf8 wins for white"; id "ZPTS.20";
8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; c0 "CCC post by Tim Foden, id MES.831, white wins, 1. Kd3 g3 2. f4 Kf1 3. Kd2+ Kg1 4. Bd7 Kf1 5. Bh3 Rg1 6. Bg4 Rh1 7. Be2+ Kg1 8. Nc3 Kf2 9. Ne4+ Kg1 10. Ng5 Kf2 11. Nh3#"; id "ZPTS.21";
4B3/8/p7/k2N4/7p/K6p/PP5P/2q5 w - - bm Ba4; c0 "CCC post by Tim Foden, id CCC.347609, white wins"; id "ZPTS.22";
6Q1/8/8/7k/8/8/3p1pp1/3Kbrrb w - - bm Qg7; c0 "CCC post by Joachim Rang, mate in 4"; id "ZPTS.23";
8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; c0 "CCC post by Joachim Rang, mate in 15, h4 is only draw"; id "ZPTS.24";
8/1B6/8/5p2/8/8/5Qrq/1K1R2bk w - - bm Qa7; c0 "CCC post by Tim Foden, id CCC.321759, mate in 3"; id "ZPTS.25";
8/3p1p2/5Ppp/K2R2bk/4pPrr/6Pp/4B2P/3N4 w - - bm Nc3; c0 "CCC post by Tim Foden, id CCC.321751, mate in 4: 1.Nc3 e3 2.Rb5 d6 3.Nd5 Bxf4 4.Nxf4#"; id "ZPTS.26";
8/8/p5p1/p2N3p/k2P3P/5P2/KP1qB3/8 w - - bm f4; c0 "white wins, derived from the more difficult ZPTS.28, Zugzwang after f4"; id "ZPTS.27";
8/p5pq/8/p2N3p/k2P3P/8/KP3PB1/8 w - - bm Be4; c0 "Kubbel 1925, 1.Be4!! Qh6 2.Bd3!! Qd2 [2...Qd6 3.b3#] 3.Be2 g6 [3...Qc2 4.Bd1 Qxd1 5.Nc3 -; 3...a6 4.f3 g6 5.f4 -] 4.f3 a6 5.f4 Qc2 6.Bd1, Zugzwang after f4, white wins"; id "ZPTS.28";
8/5p2/4b1p1/7R/5K1P/2r3B1/7N/4b1k1 w - - bm Nf3+; c0 "Noam Elkies 1984, 1 Nf3+! Rxf3+! 2 Kxf3 Bg4+! 3 Kf4!! Bxg3+ 4 Kxg4 gxh5+ 5 Kh3!! Kf1 6 Kxg3 Ke2 7 Kf4 f6 8 Kf5 Kf3 9 Kxf6 Kg4 10 Ke5 Kh4 11 Kf4, draw"; id "ZPTS.29";
5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc3; c0 "CCC post by Tim Foden, id CCC.321966, mate in 4"; id "ZPTS.30";

Posted: **26 Oct 2004, 21:09**

> 8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Bd1 Be2; c0 "CCC post by Sune Fischer, Averbakh 1954, white wins: 1.Be2 Be8 [1.-Bg6 2.Bd3 Bh7 3.Bf1 leads to instant zugzwang, be it after 3.-Bg6 4.Bg2 Bf7 5.Bf3 or after 3.-Bg8 4.Be2 Bf7 5.Bf3] 2.Bd3 Bg6 3.Bc2 Bh7 4.Bb3! Bg8 5.Bd1 Bf7 6.Bf3! and so on"; id "ZPTS.13";

I fear, this is not a good test position - at least not for automatic testing. Other moves than the two given will win, too. BTW. was posted by Sune Larsen (Larson?), not Fischer.

I will give the Yace results under different conditions. Yace has a "null move verification" by default (it is different to the method published by Omid David under verified null move or similar). Given enough depth (which may need unpractible long time) Yace should be able to solve all positions. I disabled this verification, and no surprise it did worse in the test. In this mode, Yace can fail to solve some positions even with infinite time (other engines behave similar).

Results with default settings, 60 s per position, 250M hash, P4, 2.53 GHz, TBs disabled:

1s 20s 60s
ZPTS.01: 1 (Rc6) 1 (Rc6) 1 (Rc6) 0.000
ZPTS.02: 1 (Rh8+) 1 (Rh8+) 1 (Rh8+) 0.002
ZPTS.03: 1 (Kd5) 1 (Kd5) 1 (Kd5) 0.000
ZPTS.04: 1 (Kc6) 1 (Kc6) 1 (Kc6) 0.000
ZPTS.05: 1 (Ng4) 1 (Ng4) 1 (Ng4) 0.000
ZPTS.06: 1 (a6) 1 (a6) 1 (a6) 0.219
ZPTS.07: 1 (Kb2) 1 (Kb2) 1 (Kb2) 0.006
ZPTS.08: 1 (Nc6) 1 (Nc6) 1 (Nc6) 0.025
ZPTS.09: 0 (Rb5) 0 (Ra5) 1 (Rc4) 21.312
ZPTS.10: 1 (g7) 1 (g7) 1 (g7) 0.341
ZPTS.11: 0 (Qd7+) 1 (Qd3) 1 (Qd3) 11.707
ZPTS.12: 1 (Re1+) 1 (Re1+) 1 (Re1+) 0.008
ZPTS.13: 1 (Be2) 1 (Be2) 1 (Bd1) 0.000
ZPTS.14: 0 (Qe1) 0 (Qe1) 0 (Qe1) nf
ZPTS.15: 0 (Rb5) 0 (Rb5) 1 (Ne8) 30.104
ZPTS.16: 0 (Rf1) 1 (Rf7) 1 (Rf7) 18.805
ZPTS.17: 0 (Rd8) 0 (Rd8) 1 (Nxd5) 27.879
ZPTS.18: 0 (Bh6+) 0 (Bh6+) 0 (Bf6+) nf
ZPTS.19: 0 (gxh7+) 0 (gxh7+) 0 (gxh7+) nf
ZPTS.20: 0 (Qf8) 0 (Qf8) 0 (Qf8) nf
ZPTS.21: 0 (Ne3) 0 (Ne3) 1 (Kd3) 41.617
ZPTS.22: 1 (Ba4) 1 (Ba4) 1 (Ba4) 0.004
ZPTS.23: 1 (Qg7) 1 (Qg7) 1 (Qg7) 0.384
ZPTS.24: 0 (h4) 1 (h3) 1 (h3) 1.963
ZPTS.25: 0 (Qxf5) 0 (Qxf5) 0 (Qxf5) nf
ZPTS.26: 0 (Ne3) 1 (Nc3) 1 (Nc3) 6.162
ZPTS.27: 0 (Nc3+) 1 (f4) 1 (f4) 15.579
Kubbel 1925, 1.: 0 (b3+) 0 (b3+) 0 (b3+) nf
ZPTS.29: 1 (Nf3+) 1 (Nf3+) 1 (Nf3+) 0.009
ZPTS.30: 0 (Nxh1) 0 (Rb1) 1 (Rxc3) 26.934

Summary: 14 19 24 203.060

Steve Maughan formula Sum(10.0*exp(-ln(2)*solution_time/60.0)) = 219.74

And now with the preventions to null move artefacts disabled (can only be done in source code, not by run time parameters)

1s 20s 60s
ZPTS.01: 1 (Rc6) 1 (Rc6) 1 (Rc6) 0.001
ZPTS.02: 1 (Rh8+) 1 (Rh8+) 1 (Rh8+) 0.002
ZPTS.03: 1 (Kd5) 1 (Kd5) 1 (Kd5) 0.000
ZPTS.04: 1 (Kc6) 1 (Kc6) 1 (Kc6) 0.000
ZPTS.05: 1 (Ng4) 1 (Ng4) 1 (Ng4) 0.001
ZPTS.06: 1 (a6) 1 (a6) 1 (a6) 0.219
ZPTS.07: 1 (Kb2) 1 (Kb2) 1 (Kb2) 0.007
ZPTS.08: 0 (Nf5) 1 (Nc6) 1 (Nc6) 2.891
ZPTS.09: 0 (Rb5) 0 (Ra5) 1 (Rc4) 52.953
ZPTS.10: 0 (Bc5) 0 (Bc5) 0 (Bc5) nf
ZPTS.11: 0 (Qd7+) 0 (Qd7+) 0 (Qd7+) nf
ZPTS.12: 0 (Rxa6) 0 (Rxa6) 0 (Rxa6) nf
ZPTS.13: 0 (Bg2) 0 (Bg2) 1 (Be2) 53.478
ZPTS.14: 0 (Qe1) 0 (Qe1) 0 (Qe1) nf
ZPTS.15: 0 (Rb5) 0 (Rb5) 0 (Rb5) nf
ZPTS.16: 0 (Rf1) 1 (Rf7) 1 (Rf7) 19.165
ZPTS.17: 0 (Rd8) 0 (Rd8) 0 (Rd8) nf
ZPTS.18: 0 (Bh6+) 0 (Bf6+) 0 (Bf6+) nf
ZPTS.19: 0 (gxh7+) 0 (gxh7+) 0 (gxh7+) nf
ZPTS.20: 0 (Qf8) 0 (Qf8) 0 (Qf8) nf
ZPTS.21: 0 (Ne3) 0 (Ne3) 0 (Ne3) nf
ZPTS.22: 0 (Bd7) 0 (Bd7) 0 (Bd7) nf
ZPTS.23: 0 (Qg3) 0 (Qg3) 0 (Qg3) nf
ZPTS.24: 0 (h4) 0 (h4) 0 (h4) nf
ZPTS.25: 0 (Qxf5) 0 (Qxf5) 0 (Qf1) nf
ZPTS.26: 0 (fxg5) 0 (Ne3) 0 (Ne3) nf
ZPTS.27: 0 (Nc3+) 0 (Nc3+) 0 (Nc3+) nf
Kubbel 1925, 1.: 0 (b3+) 0 (b3+) 0 (b3+) nf
ZPTS.29: 1 (Nf3+) 1 (Nf3+) 1 (Nf3+) 0.009
ZPTS.30: 0 (Nxh1) 0 (Rxa1) 0 (Rb1) nf

Summary: 8 10 12 128.726

Steve Maughan formula Sum(10.0*exp(-ln(2)*solution_time/60.0)) = 108.47

The result is even worse, than it looks. For example the default version solved pos 6 with winning score (> 6) in under one s, while the other version had only draw score after one minute.

The "Kubbel" in the table shows a small parsing bug in Yace. c0 has a ";" inside quotes ... Perhaps I had introduced this bug by purpose once, to be able to parse some not so clean epd files without much effort.

Regards,
Dieter

Posted: **26 Oct 2004, 21:20**

Sorry, I had forgotten to format the tables.

Results with default settings, 60 s per position, 250M hash, P4, 2.53 GHz, TBs disabled:

Code: Select all: 1s 20s 60s ZPTS.01: 1 (Rc6) 1 (Rc6) 1 (Rc6) 0.000 ZPTS.02: 1 (Rh8+) 1 (Rh8+) 1 (Rh8+) 0.002 ZPTS.03: 1 (Kd5) 1 (Kd5) 1 (Kd5) 0.000 ZPTS.04: 1 (Kc6) 1 (Kc6) 1 (Kc6) 0.000 ZPTS.05: 1 (Ng4) 1 (Ng4) 1 (Ng4) 0.000 ZPTS.06: 1 (a6) 1 (a6) 1 (a6) 0.219 ZPTS.07: 1 (Kb2) 1 (Kb2) 1 (Kb2) 0.006 ZPTS.08: 1 (Nc6) 1 (Nc6) 1 (Nc6) 0.025 ZPTS.09: 0 (Rb5) 0 (Ra5) 1 (Rc4) 21.312 ZPTS.10: 1 (g7) 1 (g7) 1 (g7) 0.341 ZPTS.11: 0 (Qd7+) 1 (Qd3) 1 (Qd3) 11.707 ZPTS.12: 1 (Re1+) 1 (Re1+) 1 (Re1+) 0.008 ZPTS.13: 1 (Be2) 1 (Be2) 1 (Bd1) 0.000 ZPTS.14: 0 (Qe1) 0 (Qe1) 0 (Qe1) nf ZPTS.15: 0 (Rb5) 0 (Rb5) 1 (Ne8) 30.104 ZPTS.16: 0 (Rf1) 1 (Rf7) 1 (Rf7) 18.805 ZPTS.17: 0 (Rd8) 0 (Rd8) 1 (Nxd5) 27.879 ZPTS.18: 0 (Bh6+) 0 (Bh6+) 0 (Bf6+) nf ZPTS.19: 0 (gxh7+) 0 (gxh7+) 0 (gxh7+) nf ZPTS.20: 0 (Qf8) 0 (Qf8) 0 (Qf8) nf ZPTS.21: 0 (Ne3) 0 (Ne3) 1 (Kd3) 41.617 ZPTS.22: 1 (Ba4) 1 (Ba4) 1 (Ba4) 0.004 ZPTS.23: 1 (Qg7) 1 (Qg7) 1 (Qg7) 0.384 ZPTS.24: 0 (h4) 1 (h3) 1 (h3) 1.963 ZPTS.25: 0 (Qxf5) 0 (Qxf5) 0 (Qxf5) nf ZPTS.26: 0 (Ne3) 1 (Nc3) 1 (Nc3) 6.162 ZPTS.27: 0 (Nc3+) 1 (f4) 1 (f4) 15.579 Kubbel 1925, 1.: 0 (b3+) 0 (b3+) 0 (b3+) nf ZPTS.29: 1 (Nf3+) 1 (Nf3+) 1 (Nf3+) 0.009 ZPTS.30: 0 (Nxh1) 0 (Rb1) 1 (Rxc3) 26.934 Summary: 14 19 24 203.060

And now with the preventions to null move artefacts disabled (can only be done in source code, not by run time parameters)

Code: Select all: 1s 20s 60s ZPTS.01: 1 (Rc6) 1 (Rc6) 1 (Rc6) 0.001 ZPTS.02: 1 (Rh8+) 1 (Rh8+) 1 (Rh8+) 0.002 ZPTS.03: 1 (Kd5) 1 (Kd5) 1 (Kd5) 0.000 ZPTS.04: 1 (Kc6) 1 (Kc6) 1 (Kc6) 0.000 ZPTS.05: 1 (Ng4) 1 (Ng4) 1 (Ng4) 0.001 ZPTS.06: 1 (a6) 1 (a6) 1 (a6) 0.219 ZPTS.07: 1 (Kb2) 1 (Kb2) 1 (Kb2) 0.007 ZPTS.08: 0 (Nf5) 1 (Nc6) 1 (Nc6) 2.891 ZPTS.09: 0 (Rb5) 0 (Ra5) 1 (Rc4) 52.953 ZPTS.10: 0 (Bc5) 0 (Bc5) 0 (Bc5) nf ZPTS.11: 0 (Qd7+) 0 (Qd7+) 0 (Qd7+) nf ZPTS.12: 0 (Rxa6) 0 (Rxa6) 0 (Rxa6) nf ZPTS.13: 0 (Bg2) 0 (Bg2) 1 (Be2) 53.478 ZPTS.14: 0 (Qe1) 0 (Qe1) 0 (Qe1) nf ZPTS.15: 0 (Rb5) 0 (Rb5) 0 (Rb5) nf ZPTS.16: 0 (Rf1) 1 (Rf7) 1 (Rf7) 19.165 ZPTS.17: 0 (Rd8) 0 (Rd8) 0 (Rd8) nf ZPTS.18: 0 (Bh6+) 0 (Bf6+) 0 (Bf6+) nf ZPTS.19: 0 (gxh7+) 0 (gxh7+) 0 (gxh7+) nf ZPTS.20: 0 (Qf8) 0 (Qf8) 0 (Qf8) nf ZPTS.21: 0 (Ne3) 0 (Ne3) 0 (Ne3) nf ZPTS.22: 0 (Bd7) 0 (Bd7) 0 (Bd7) nf ZPTS.23: 0 (Qg3) 0 (Qg3) 0 (Qg3) nf ZPTS.24: 0 (h4) 0 (h4) 0 (h4) nf ZPTS.25: 0 (Qxf5) 0 (Qxf5) 0 (Qf1) nf ZPTS.26: 0 (fxg5) 0 (Ne3) 0 (Ne3) nf ZPTS.27: 0 (Nc3+) 0 (Nc3+) 0 (Nc3+) nf Kubbel 1925, 1.: 0 (b3+) 0 (b3+) 0 (b3+) nf ZPTS.29: 1 (Nf3+) 1 (Nf3+) 1 (Nf3+) 0.009 ZPTS.30: 0 (Nxh1) 0 (Rxa1) 0 (Rb1) nf Summary: 8 10 12 128.726

Steve Maughan formula Sum(10.0*exp(-ln(2)*solution_time/60.0)) = 108.47

Dieter

Posted: **06 Nov 2004, 11:05**

I have to say that one advantage of the new forum is that if one is away for some time (I have been away for almost 2 weeks), it is still easy and very quick to find interesting posts that have been done in the meantime. With the old forum e.g. I am sure I would have never seen this one ...

Thanks for posting the interesting results, what I take out of this is:
a) your nullmove verification scheme works very well
b) the test suite seems to be a usable tool to measure the quality of zugzwang detection in an engine (demonstrated now in Fruit and in Yace)

Of course - this is a disclaimer :wink:

- doing better in Zugzwang positions has not too much to do with being stronger overall.

I have fixed the two small issues you mention (put Sune Larsen there, and also removed the ; in the comment, because something like this is probably asking for trouble with some parsers, better to avoid this).

I am aware that some of the positions are not ideal for an automatic test suite. I have also observed in some cases an engine bringing up the right move, but only seeing a draw instead of a win. So I do think this is probably not a test suite that can be applied blindly, but one needs to go through the results briefly. e.g. I decided for Fruit to count a position where it comes up with the right move, but does not have a clue what is going on as "not solved".
Even with this limitation I still think it is a helpful tool.

ZPTS positions with the two minor issues (comments) changed:

3k4/8/4K3/2R5/8/8/8/8 w - - bm Rc1 Rc2 Rc3 Rc4 Rc6; c0 "CCC post"; id "ZPTS.01";
1k6/7R/2K5/8/8/8/8/8 w - - bm Re7 Rf7 Rg7 Rh1 Rh2 Rh3 Rh4 Rh5 Rh6 Rh8+; c0 "CCC post"; id "ZPTS.02";
8/3k4/8/8/3PK3/8/8/8 w - - bm Kd5; c0 "CCC post"; id "ZPTS.03";
2k5/8/1K1P4/8/8/8/8/8 w - - bm Kc6; c0 "white wins"; id "ZPTS.04";
8/8/8/4N3/8/7p/8/5K1k w - - bm Ng4; c0 "white mates"; id "ZPTS.05";
8/8/1p1K4/Pp6/2k1p3/8/1P6/8 w - - bm a6; c0 "Kubbel 1927, 1 ... e3 2 a7 e2 3 a8/Q e1/Q 4 Qd5+ Kb4 5 Qd3!, white wins"; id "ZPTS.06";
8/1p5k/1P1p4/3p4/3Pp2p/2K1P2p/7P/8 w - - bm Kb2; c0 "1 Kb2! Kg8 2 Ka1!!, draw"; id "ZPTS.07";
8/4N3/8/8/8/2b1p3/p1K1P3/k7 w - - bm Nc6; c0 "white mates in 3"; id "ZPTS.08";
8/8/7p/2R5/4pp1K/8/8/3k2b1 w - - bm Rc4; c0 "Kricheli 1986, 1 Rc4! e3 2 Rd4+! Kc2 3 Rxf4 e2 4 Re4 Kd2 5 Rxe2+ Kxe2 6 Kg4!, draw"; id "ZPTS.09";
4KBkr/7p/6PP/4P3/8/3P1p2/8/8 w - - bm g7; c0 "CCC post 27.4.2004 by Gerd Isenberg, white wins"; id "ZPTS.10";
8/p7/1p6/p7/kq1Q4/8/K7/8 w - - bm Qd3; c0 "post in Avler chess forum, mate in 13: 1.Qd3 a6 2.Qd7+ Qb5 3.Qd4+ Qb4 4.Qd3 Qb2+ 5.Kxb2 Kb4 6.Qc3+ Kb5 7.Qc7 Kb4 8.Qc6 a4 9.Kc2 a3 10.Qc3+ Ka4 11.Qc4+ Ka5 12.Kb3 b5 13.Qc7#"; id "ZPTS.11";
8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - bm Re1+; c0 "CCC post by Eduard Nemeth, mate in 7"; id "ZPTS.12";
8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Bd1 Be2; c0 "CCC post by Sune Larsen, Averbakh 1954, white wins: 1.Be2 Be8 [1.-Bg6 2.Bd3 Bh7 3.Bf1 leads to instant zugzwang, be it after 3.-Bg6 4.Bg2 Bf7 5.Bf3 or after 3.-Bg8 4.Be2 Bf7 5.Bf3] 2.Bd3 Bg6 3.Bc2 Bh7 4.Bb3! Bg8 5.Bd1 Bf7 6.Bf3! and so on"; id "ZPTS.13";
6k1/3p4/P2P4/8/5Kp1/1p4Q1/p5p1/b7 w - - bm Qxg2; c0 "Kasparyan 1959, 1 ... Be5+ 2 Kf5! a1/Q 3 a7! Qxa7 4 Kg6! Qa1! 5 Qd5! Kh8 6 Qe4!!, white wins"; id "ZPTS.14";
1r4RK/2n5/7k/8/8/8/8/8 b - - bm Ne8; c0 "Polgar - Kasparov, 1996: mate in 8: 1. ... Ne8 2.Rf8 Kg6 3.Rg8+ Kf7 4.Kh7 Rb5 5.Rf8+ Kxf8 6.Kg6 Rc5 7.Kh6 Kf7 8.Kh7 Rh5#"; id "ZPTS.15";
k2N2K1/8/8/8/5R2/3n4/3p4/8 w - - bm Rf7; c0 "CCC post by Ed Schroeder, Troitzky"; id "ZPTS.16";
8/8/1p1r1k2/p1pPN1p1/P3KnP1/1P6/8/3R4 b - - bm Nxd5; c0 "CCC post 27.4.2004 by Gerd Isenberg"; id "ZPTS.17";
8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - bm Qxh4+; c0 "CCC post 10.9.2004 by Alvaro Begue"; id "ZPTS.18";
n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; c0 "CCC post, mate in 12: 1.Bc7 Qxc8 2.gxf7+ Kh8 3.Be5 Qc5 4.Bb2 Nc7 5.Ba1 a4 6.Bb2 a3 7.Ba1 a2 8.Bb2 a1Q 9.Bxa1 Nd5+ 10.Ke6+ Nc3 11.Bxc3+ Qe5+ 12.Bxe5#"; id "ZPTS.19";
3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; c0 "CCC post, draw, but h5 after Qf8 wins for white"; id "ZPTS.20";
8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; c0 "CCC post by Tim Foden, id MES.831, white wins, 1. Kd3 g3 2. f4 Kf1 3. Kd2+ Kg1 4. Bd7 Kf1 5. Bh3 Rg1 6. Bg4 Rh1 7. Be2+ Kg1 8. Nc3 Kf2 9. Ne4+ Kg1 10. Ng5 Kf2 11. Nh3#"; id "ZPTS.21";
4B3/8/p7/k2N4/7p/K6p/PP5P/2q5 w - - bm Ba4; c0 "CCC post by Tim Foden, id CCC.347609, white wins"; id "ZPTS.22";
6Q1/8/8/7k/8/8/3p1pp1/3Kbrrb w - - bm Qg7; c0 "CCC post by Joachim Rang, mate in 4"; id "ZPTS.23";
8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; c0 "CCC post by Joachim Rang, mate in 15, h4 is only draw"; id "ZPTS.24";
8/1B6/8/5p2/8/8/5Qrq/1K1R2bk w - - bm Qa7; c0 "CCC post by Tim Foden, id CCC.321759, mate in 3"; id "ZPTS.25";
8/3p1p2/5Ppp/K2R2bk/4pPrr/6Pp/4B2P/3N4 w - - bm Nc3; c0 "CCC post by Tim Foden, id CCC.321751, mate in 4: 1.Nc3 e3 2.Rb5 d6 3.Nd5 Bxf4 4.Nxf4#"; id "ZPTS.26";
8/8/p5p1/p2N3p/k2P3P/5P2/KP1qB3/8 w - - bm f4; c0 "white wins, derived from the more difficult ZPTS.28, Zugzwang after f4"; id "ZPTS.27";
8/p5pq/8/p2N3p/k2P3P/8/KP3PB1/8 w - - bm Be4; c0 "Kubbel 1925, 1.Be4!! Qh6 2.Bd3!! Qd2 [2...Qd6 3.b3#] 3.Be2 g6 [3...Qc2 4.Bd1 Qxd1 5.Nc3 -, 3...a6 4.f3 g6 5.f4 -] 4.f3 a6 5.f4 Qc2 6.Bd1, Zugzwang after f4, white wins"; id "ZPTS.28";
8/5p2/4b1p1/7R/5K1P/2r3B1/7N/4b1k1 w - - bm Nf3+; c0 "Noam Elkies 1984, 1 Nf3+! Rxf3+! 2 Kxf3 Bg4+! 3 Kf4!! Bxg3+ 4 Kxg4 gxh5+ 5 Kh3!! Kf1 6 Kxg3 Ke2 7 Kf4 f6 8 Kf5 Kf3 9 Kxf6 Kg4 10 Ke5 Kh4 11 Kf4, draw"; id "ZPTS.29";
5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc3; c0 "CCC post by Tim Foden, id CCC.321966, mate in 4"; id "ZPTS.30";

Winboard Forum

ZPTS Zugzwang Testsuite - again updated and hopefully final

ZPTS Zugzwang Testsuite - again updated and hopefully final

Re: ZPTS Zugzwang Testsuite - again updated and hopefully fi

Re: ZPTS Zugzwang Testsuite - again updated and hopefully fi

Re: ZPTS Zugzwang Testsuite - again updated and hopefully fi