New Zugzwang Testsuite

[Robert Allgeuer]

I have collected Zugzwang positions from various sources (CCC, Rebel, Internet, Books etc.) and put them together into a small testsuite of Zugzwang positions. There is no originality to this, but having those positions in one place may be interesting for some people, I hope.
It is obvious that running this test suite only makes sense without tablebases.
All comments welcome!

Robert


8/8/1p1r1k2/p1pPN1p1/P3KnP1/1P6/8/3R4 b - - bm Nxd5; id "ZPTS.01"; CCC post 27.4.2004 by Gerd Isenberg
4KBkr/7p/6PP/4P3/8/3P1p2/8/8 w - - bm g7; id "ZPTS.02"; CCC post 27.4.2004 by Gerd Isenberg
8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - bm Qxh4; id "ZPTS.03"; CCC post 10.9.2004 by Alvaro Begue
8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; id "ZPTS.04"; CCC post by Joachim Rang, mate in 15
6Q1/8/8/7k/8/8/3p1pp1/3Kbrrb w - - bm Qg7; id "ZPTS.05"; CCC post by Joachim Rang, mate in 4
n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; id "ZPTS.06"; CCC post
3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; id "ZPTS.07"; CCC post
8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; id "ZPTS.08"; CCC post by Tim Foden, id "MES.831"
8/3p1p2/5Ppp/K2R2bk/4pPrr/6Pp/4B2P/3N4 w - - bm Nc3; id "ZPTS.09"; CCC post by Tim Foden, id "CCC.321751"
8/1B6/8/5p2/8/8/5Qrq/1K1R2bk w - - bm Qa7; id "ZPTS.10"; CCC post by Tim Foden, id "CCC.321759"
5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc4; id "ZPTS.11"; CCC post by Tim Foden, id "CCC.321966"
4B3/8/p7/k2N4/7p/K6p/PP5P/2q5 w - - bm Ba4; id "ZPTS.12"; CCC post by Tim Foden, id "CCC.347609"
3k4/8/4K3/2R5/8/8/8/8 w - - bm Rc6; id "ZPTS.13"; CCC post
1k6/7R/2K5/8/8/8/8/8 w - - bm Rh8; id "ZPTS.14"; CCC post
8/3k4/8/8/3PK3/8/8/8 w - - bm Kd5; id "ZPTS.15"; CCC post
2k5/8/1K1P4/8/8/8/8/8 w - - bm Kc6; id "ZPTS.16"; white wins
1b6/8/8/7p/6k1/6P1/8/6K1 w - - bm Kg2; id "ZPTS.17"; CCC post by Dr. Robert Hyatt, draw
k2N2K1/8/8/8/5R2/3n4/3p4/8 w - - bm Rf7; id "ZPTS.18"; CCC post by Ed Schroeder, Troitzky
2n5/8/Pp5n/5N2/8/5k2/3P4/7K w - - bm d4; id "ZPTS.19"; CCC post by Ed Schroeder, Troitzky
8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Be2; id "ZPTS.20"; CCC post by Sune Fischer, white wins
8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - bm Re1; id "ZPTS.21"; CCC post by Eduard Nemeth, mate in 7
8/p7/1p6/p7/kq1Q4/8/K7/8 w - - bm Qd3; id "ZPTS.22"; post in Avler chess forum
8/8/8/4N3/8/7p/8/5K1k w - - bm Ng4; id "ZPTS.23"; white mates
1r4RK/2n5/7k/8/8/8/8/8 b - - bm Ne8; id "ZPTS.24"; Polgar - Kasparov, 1996: black wins after 91. Rf8, Kg6 92. Rg8+, Kf7
8/8/1p1K4/Pp6/2k1p3/8/1P6/8 w - - bm a6; id "ZPTS.25"; Kubbel 1927, 1 ... e3 2 a7 e2 3 a8/Q e1/Q 4 Qd5+ Kb4 5 Qd3!, white wins
6k1/3p4/P2P4/8/5Kp1/1p4Q1/p5p1/b7 w - - bm Qxg2; id "ZPTS.26"; Kasparyan 1959, 1 ... Be5+ 2 Kf5! a1/Q 3 a7! Qxa7 4 Kg6! Qa1! 5 Qd5! Kh8 6 Qe4!!, white wins
8/5p2/4b1p1/7R/5K1P/2r3B1/7N/4b1k1 w - - bm Nf3; id "ZPTS.27"; 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
8/8/7p/2R5/4pp1K/8/8/3k2b1 w - - bm Rc4; id "ZPTS.28"; Kricheli 1986, 1 Rc4! e3 2 Rd4+! Kc2 3 Rxf4 e2 4 Re4 Kd2 5 Rxe2+ Kxe2 6 Kg4!, draw
8/1p5k/1P1p4/3p4/3Pp2p/2K1P2p/7P/8 w - - bm Kb2; id "ZPTS.29"; 1 Kb2! Kg8 2 Ka1!!, draw
8/3p1N2/8/4B3/2K2p2/b3P3/pP2P3/k7 b - - bm d6; id "ZPTS.30"; Noam Elkies 1987, 1 ... d6! 2 Bc3!! Bxb2 3 Kb3! Bxc3 4 Kc2 fxe3 5 Nd6 Ba5! 6 Nf5 Bb6 7 Ne7 Bd4 8 Nd5 Bc5 9 Nf4 Bb4(d6,e7,f8) 10 Ne6 Bc5! 11 Nd8! Bd4 12 Nb7! Bb6 13 Kc1!, mate in 16

[David Weller]

Hi Robert,

I was excited to see and run GES on your suite, but....

I missed quite a few....so I disabled Null-Move ....and tried again with little improvement, ... so I ran the following on crafty to see if GES was just crazy, and it missed them too [ 30sec/pos]

8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; id "ZPTS.04";
n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; id "ZPTS.06";
3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; id "ZPTS.07";
8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; id "ZPTS.08";
5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc4; id "ZPTS.11";
k2N2K1/8/8/8/5R2/3n4/3p4/8 w - - bm Rf7; id "ZPTS.18";
2n5/8/Pp5n/5N2/8/5k2/3P4/7K w - - bm d4; id "ZPTS.19";
8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Be2; id "ZPTS.20";
6k1/3p4/P2P4/8/5Kp1/1p4Q1/p5p1/b7 w - - bm Qxg2; id "ZPTS.26";
8/3p1N2/8/4B3/2K2p2/b3P3/pP2P3/k7 b - - bm d6; id "ZPTS.30";

[David Weller]

8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; id "ZPTS.04";

is h4 a draw too?

5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc4; id "ZPTS.11"; --- should be Rxc3

8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; id "ZPTS.08";

is Nc3 a draw too?

[Klaus Friedel]

I think most of the positions are to artificial to be used to optimize a engine for avoiding null move effects. Besides that I think ZPTS.11 should be changed:

ZPTS.11: c1c3 mates as well (#4)

Regards,

Klaus

[Robert Allgeuer]

ZPTS 4:
According to the original post the solution h3 is a mate in 15., h4 is only a draw.

ZPTS 8:
in fact white wins, a mate in 11
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#
Nc3 does not win.
It is true that for a testsuite run this is not a particularly good position, because an engine may also do Kd3 with a draw score, without really seeing the problem, the real solution is in fact only if the engine sees the win. For testing Zugzwang it may still be useful.
Same thing btw for ZPTS 16

ZPTS 11:
Yes this is an error, in fact Rxc3 is the only solution. Rxc4 is illegal.


Various positions are somewhat unrealistic, in particular the non-endgame ones, but I reckon this comes with the theme.
Furthermore for many of the positions the original posts stated that Crafty does not solve them. I tried Aristarch and it solved less than 10. I think generally the positions are mostly hard.


corrected:
8/8/1p1r1k2/p1pPN1p1/P3KnP1/1P6/8/3R4 b - - bm Nxd5; id "ZPTS.01"; CCC post 27.4.2004 by Gerd Isenberg
4KBkr/7p/6PP/4P3/8/3P1p2/8/8 w - - bm g7; id "ZPTS.02"; CCC post 27.4.2004 by Gerd Isenberg
8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - bm Qxh4; id "ZPTS.03"; CCC post 10.9.2004 by Alvaro Begue
8/8/8/2p5/1pp5/brpp4/1pprp2P/qnkbK3 w - - bm h3; id "ZPTS.04"; CCC post by Joachim Rang, mate in 15, h4 is only draw
6Q1/8/8/7k/8/8/3p1pp1/3Kbrrb w - - bm Qg7; id "ZPTS.05"; CCC post by Joachim Rang, mate in 4
n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; id "ZPTS.06"; CCC post
3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; id "ZPTS.07"; CCC post
8/8/8/1B6/6p1/8/4KPpp/3N2kr w - - bm Kd3 Ke3; id "ZPTS.08"; 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#
8/3p1p2/5Ppp/K2R2bk/4pPrr/6Pp/4B2P/3N4 w - - bm Nc3; id "ZPTS.09"; CCC post by Tim Foden, id "CCC.321751"
8/1B6/8/5p2/8/8/5Qrq/1K1R2bk w - - bm Qa7; id "ZPTS.10"; CCC post by Tim Foden, id "CCC.321759"
5R2/2K5/1pP5/4k2p/3pp3/2p4N/B4N1b/n1R1B2b w - - bm Rxc3; id "ZPTS.11"; CCC post by Tim Foden, id "CCC.321966"
4B3/8/p7/k2N4/7p/K6p/PP5P/2q5 w - - bm Ba4; id "ZPTS.12"; CCC post by Tim Foden, id "CCC.347609"
3k4/8/4K3/2R5/8/8/8/8 w - - bm Rc6; id "ZPTS.13"; CCC post
1k6/7R/2K5/8/8/8/8/8 w - - bm Rh8; id "ZPTS.14"; CCC post
8/3k4/8/8/3PK3/8/8/8 w - - bm Kd5; id "ZPTS.15"; CCC post
2k5/8/1K1P4/8/8/8/8/8 w - - bm Kc6; id "ZPTS.16"; white wins
1b6/8/8/7p/6k1/6P1/8/6K1 w - - bm Kg2; id "ZPTS.17"; CCC post by Dr. Robert Hyatt, draw
k2N2K1/8/8/8/5R2/3n4/3p4/8 w - - bm Rf7; id "ZPTS.18"; CCC post by Ed Schroeder, Troitzky
2n5/8/Pp5n/5N2/8/5k2/3P4/7K w - - bm d4; id "ZPTS.19"; CCC post by Ed Schroeder, Troitzky
8/5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Be2; id "ZPTS.20"; CCC post by Sune Fischer, white wins
8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - bm Re1; id "ZPTS.21"; CCC post by Eduard Nemeth, mate in 7
8/p7/1p6/p7/kq1Q4/8/K7/8 w - - bm Qd3; id "ZPTS.22"; post in Avler chess forum
8/8/8/4N3/8/7p/8/5K1k w - - bm Ng4; id "ZPTS.23"; white mates
1r4RK/2n5/7k/8/8/8/8/8 b - - bm Ne8; id "ZPTS.24"; Polgar - Kasparov, 1996: black wins after 91. Rf8, Kg6 92. Rg8+, Kf7
8/8/1p1K4/Pp6/2k1p3/8/1P6/8 w - - bm a6; id "ZPTS.25"; Kubbel 1927, 1 ... e3 2 a7 e2 3 a8/Q e1/Q 4 Qd5+ Kb4 5 Qd3!, white wins
6k1/3p4/P2P4/8/5Kp1/1p4Q1/p5p1/b7 w - - bm Qxg2; id "ZPTS.26"; Kasparyan 1959, 1 ... Be5+ 2 Kf5! a1/Q 3 a7! Qxa7 4 Kg6! Qa1! 5 Qd5! Kh8 6 Qe4!!, white wins
8/5p2/4b1p1/7R/5K1P/2r3B1/7N/4b1k1 w - - bm Nf3; id "ZPTS.27"; 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
8/8/7p/2R5/4pp1K/8/8/3k2b1 w - - bm Rc4; id "ZPTS.28"; Kricheli 1986, 1 Rc4! e3 2 Rd4+! Kc2 3 Rxf4 e2 4 Re4 Kd2 5 Rxe2+ Kxe2 6 Kg4!, draw
8/1p5k/1P1p4/3p4/3Pp2p/2K1P2p/7P/8 w - - bm Kb2; id "ZPTS.29"; 1 Kb2! Kg8 2 Ka1!!, draw
8/3p1N2/8/4B3/2K2p2/b3P3/pP2P3/k7 b - - bm d6; id "ZPTS.30"; Noam Elkies 1987, 1 ... d6! 2 Bc3!! Bxb2 3 Kb3! Bxc3 4 Kc2 fxe3 5 Nd6 Ba5! 6 Nf5 Bb6 7 Ne7 Bd4 8 Nd5 Bc5 9 Nf4 Bb4(d6,e7,f8) 10 Ne6 Bc5! 11 Nd8! Bd4 12 Nb7! Bb6 13 Kc1!, mate in 16

[Dann Corbit]

1k6/7R/2K5/8/8/8/8/8 w - - acn 542; acs 0; bm Re7 Rf7 Rg7 Rh1 Rh2 Rh3 Rh4 Rh5 Rh6 Rh8+; c0 "CCC post"; ce 32762; dm 3; id "ZPTS.14"; pv Rh8+ Ka7 Rg8 Ka6 Ra8#;

[Anonymous]

Thanks Robert! Some comments

8/8/1p1r1k2/p1pPN1p1/P3KnP1/1P6/8/3R4 b - - bm Nxd5; id "ZPTS.01"; CCC post 27.4.2004 by Gerd Isenberg

It is nice, that you give more info to the positions, like here "CCC post 27.4.2004 by Gerd Isenberg", and in some other positions, you give the lines. But it is formally not totally correct. Better would be :

... ; c0 "CCC post 27.4.2004 by Gerd Isenberg";

or c1, c2 ... instead of c0.


8/6B1/p5p1/Pp4kp/1P5r/5P1Q/4q1PK/8 w - - bm Qxh4; id "ZPTS.03"; CCC post 10.9.2004 by Alvaro Begue

I think, the checking sign belongs to a SAN move (a SAN move is required in EPD), so: bm Qxh4+; (and a few times more further down the same thing)

n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - bm Bc7; id "ZPTS.06"; CCC post

Very difficult for Yace. Which engines will solve this?

3nQ1k1/p2P2p1/1p6/8/5q1P/8/PP6/1K6 b - - bm Kh7; id "ZPTS.07"; CCC post


Perhaps add: c0 "Qf8 loses after h5". Any engines that give a good score after Qf8?

1k6/7R/2K5/8/8/8/8/8 w - - bm Rh8; id "ZPTS.14"; CCC post

bm Rh8+;

1b6/8/8/7p/6k1/6P1/8/6K1 w - - bm Kg2; id "ZPTS.17"; CCC post by Dr. Robert Hyatt, draw

Is this pos correct? Kh2 loses, all other moves draw!?

2n5/8/Pp5n/5N2/8/5k2/3P4/7K w - - bm d4; id "ZPTS.19"; CCC post by Ed Schroeder, Troitzky

Is this pos correct? After d4 I get:

14/29 0:47 +M19 1...Nxf5 2.d5 Kg3 3.Kg1 b5 4.Kf1 Ne3+
5.Ke1 Nxd5 6.Kf1 Nc7 7.a7 Nxa7 8.Ke1 Nc6
9.Kf1 Na5 10.Ke1 b4 11.Ke2 Nb5
12.Ke3 b3 13.Kd2 Kg4 14.Ke2 b2 (30.292.208) 637



8/8/p3R3/1p5p/1P5p/6rp/5K1p/7k w - - bm Re1; id "ZPTS.21"; CCC post by Eduard Nemeth, mate in 7

bm Re1+;

8/5p2/4b1p1/7R/5K1P/2r3B1/7N/4b1k1 w - - bm Nf3; id "ZPTS.27"; 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

bm Nf3+;


8/3p1N2/8/4B3/2K2p2/b3P3/pP2P3/k7 b - - bm d6; id "ZPTS.30"; Noam Elkies 1987, 1 ... d6! 2 Bc3!! Bxb2 3 Kb3! Bxc3 4 Kc2 fxe3 5 Nd6 Ba5! 6 Nf5 Bb6 7 Ne7 Bd4 8 Nd5 Bc5 9 Nf4 Bb4(d6,e7,f8) 10 Ne6 Bc5! 11 Nd8! Bd4 12 Nb7! Bb6 13 Kc1!, mate in 16

Black to move, and white wins after black bm??

You might find some more interesting Zugzwang positions on Eduard Nemeth's home page.

Regards,
Dieter

[Anonymous]

You might find some more interesting Zugzwang positions on Eduard Nemeth's home page.

THis sounds ambiguous. I did not mean, that those positions were more interesting than the ones you gave in this thread. Just that it might be interesting to add some to a collection of Zugzwang positions

Dieter

[Mike Scheidl]

The collection is interesting, but it seems to me there are still some doubts or corrections necessary (?). To those involved, please indicate with a new posting title like "Zugzwang final version" then, thanks!

(lazy... 8) )

[Robert Allgeuer]

Thanks for the feedback.
It was my intention to get feedback, corrections etc. incorporate it and then re-post it. Whether it will then be final is another question ...

I have to go through Dieter's post in more detail, but thanks for this hint with c0. Nevertheless, for the uninitiated: What do c0, c1 and c2 mean exactly?
In fact, looking at the lct2, gs2940 etc. epd files that I have, they do not use c0, c1 , c2 either, but maybe this is a newer way of writing it which I will happily incorporate.

Is there an epd standard somewhere out there describing these sort of things?

I will also check out Eduard Nemeth's site.

Thanks
Robert

[Robert Allgeuer]

1k6/7R/2K5/8/8/8/8/8 w - - acn 542; acs 0; bm Re7 Rf7 Rg7 Rh1 Rh2 Rh3 Rh4 Rh5 Rh6 Rh8+; c0 "CCC post"; ce 32762; dm 3; id "ZPTS.14"; pv Rh8+ Ka7 Rg8 Ka6 Ra8#;

further to that:
what does acn, acs, ce and dm mean.
Why no ; before acn

Thanks
Robert

[Anonymous]

Nevertheless, for the uninitiated: What do c0, c1 and c2 mean exactly?
[...]
Is there an epd standard somewhere out there describing these sort of things?

C for comment. It is in the PGN standard, for example at http://scid.sourceforge.net/doc/standard.txt

---
16.2.5.5: Opcode "c0": comment (primary, also "c1" though "c9")

The opcode "c0" (lower case letter "c", digit character zero) indicates a top
level comment that applies to the given position. It is the first of ten
ranked comments, each of which has a mnemonic formed from the lower case letter
"c" followed by a single decimal digit. Each of these opcodes takes either a
single string operand or no operand at all.

This ten member comment family of opcodes is intended for use as descriptive
commentary for a complete game or game fragment. The usual processing of these
opcodes are as follows:

1) At the beginning of a game (or game fragment), a move sequence scanning
program initializes each element of its set of ten comment string registers to
be null.

2) As the EPD record for each position in the game is processed, the comment
operations are interpreted from left to right. (Actually, all operations in n
EPD record are interpreted from left to right.) Because operations appear in
ASCII order according to their opcode mnemonics, opcode "c0" (if present) will
be handled prior to all other opcodes, then opcode "c1" (if present), and so
forth until opcode "c9" (if present).

3) The processing of opcode "cN" (0 <= N <= 9) involves two steps. First, all
comment string registers with an index equal to or greater than N are set to
null. (This is the set "cN" though "c9".) Second, and only if a string
operand is present, the value of the corresponding comment string register is
set equal to the string operand.
---

Some more comments to the positions. Several positions have a (short) forced mate as a solution, and besides the suggested bm, many other moves win, too. Perhaps this should be noted. Some people may think, it is important for an engine to be able to find the shortest mate, others won't care. BTW. Yace needed depth 12 to find one mate in 3 (pos 100).

IMHO the KRK positions are not really useful. Any engine should solve them (the KPK, too) - at least in the sense that it should be able to win. If not, it might be a design decision or just a bug.

1k6/7R/2K5/8/8/8/8/8 w - - bm Rh8; id "ZPTS.14"; CCC post
Several moves that mate in 3.

5b2/p2k4/1p1p1p1p/1P1K1P1P/2P1PB2/8/8 w - - bm Be2; id "ZPTS.20"; CCC post by Sune Fischer, white wins

Other moves win, too, in practically the same way as Be2. I tried Yace and Shredder. Both are able to win from this position with white, while the root move changes several times (for example from Be2 to Bd1 and back).

Regards,
Dieter

[F.Huber]

1k6/7R/2K5/8/8/8/8/8 w - - acn 542; acs 0; bm Re7 Rf7 Rg7 Rh1 Rh2 Rh3 Rh4 Rh5 Rh6 Rh8+; c0 "CCC post"; ce 32762; dm 3; id "ZPTS.14"; pv Rh8+ Ka7 Rg8 Ka6 Ra8#;

further to that:
what does acn, acs, ce and dm mean.
Why no ; before acn

Thanks
Robert

Hi Robert,

here?s a link to a complete description of PGN/EPD/FEN-Standard including all those special keywords above:
http://www.drb.insel.de/~heiner/Chess/PGN_Standard.txt

Regards,
Franz.