Simpel test positions

[Henk]

[d] 3rrbk1/2qb1ppp/p1pp1nn1/1p6/2PNPP2/1PNQ3P/PB4P1/1B2RR1K b - - 0 1

Best move for black b4!!


[d] r1bq1rk1/pppnbppp/3p1n2/4p3/2PPP3/2NB1N2/PP3PPP/R1BQ1RK1 b - - 4 7

Best move for black e5xd4!

[Henk]

Unfortunately Stockfish 7 does not agree. It gives Qb7 and c6.

[flok]

1 minute think time, Embla says: b5-b4 for the first and f8-e8 for the second.

Code: Select all

info depth 1 seldepth 8 score cp -2 time 13 nodes 84 pv c6c5
info depth 2 seldepth 14 score cp 1 time 27 nodes 581 pv c6c5 d4e2
info depth 3 seldepth 14 score cp 2 time 30 nodes 1281 pv c6c5 d4e2 b5b4
info depth 4 seldepth 18 score cp 100 time 38 nodes 4182 pv b5b4
info depth 4 seldepth 18 score cp 102 time 42 nodes 5998 pv b5b4 c3e2
info depth 5 seldepth 26 score cp 26 time 80 nodes 19677 pv b5b4 c3e2
info depth 5 seldepth 21 score cp 16 time 110 nodes 31026 pv b5b4 c3d1 c6c5 f4f5 c5d4 f5g6
info depth 6 seldepth 28 score cp 92 time 129 nodes 38001 pv b5b4
info depth 6 seldepth 29 score cp 108 time 207 nodes 67940 pv b5b4 c3e2 c6c5 e4e5 d6e5 f4e5 g6e5 e5f6
info depth 7 seldepth 28 score cp 108 time 314 nodes 112024 pv b5b4 c3e2 c6c5 e4e5 d6e5 f4e5 g6e5
info depth 8 seldepth 31 score cp 107 time 722 nodes 281331 pv b5b4 c3e2 c6c5 d4f3 f6e4 b1c2 d7c6 f4f5
info depth 9 seldepth 37 score cp 100 time 2211 nodes 877154 pv b5b4 c3e2 c6c5 d4c2 f6e4 f4f5 g6h4 c2e3 d7c6
info depth 10 seldepth 38 score cp 25 time 5634 nodes 2301711 pv b5b4 c3e2 c6c5 d4c2 f6e4 f4f5 g6h4 c2e3 d7c6
info depth 10 seldepth 39 score cp 25 time 6568 nodes 2646191 pv b5b4
info depth 11 seldepth 41 score cp 38 time 10269 nodes 4167171 pv b5b4 c3d1 c6c5 d4c2 d7c6 b2f6 g7f6 g2g4 f8g7 d1b2 h7h6
info depth 12 seldepth 44 score cp 32 time 19668 nodes 8391551 pv b5b4 c3d1 c6c5 d4c2 d7c6 b2f6 g7f6 f4f5 g6e5 d3e3 f8g7 d1f2
info depth 13 seldepth 46 score cp 32 time 35905 nodes 16283038 pv b5b4 c3d1 c6c5 d4c2 d7c6 b2f6 g7f6 f4f5 g6e5 d3e3 f8g7 d1f2 h7h6
info score cp 32
bestmove b5b4

Code: Select all

info depth 1 seldepth 4 score cp -5 time 6 nodes 38 pv f8e8
info depth 2 seldepth 12 score cp -8 time 24 nodes 325 pv e5d4 f3d4
info depth 3 seldepth 14 score cp -5 time 28 nodes 1015 pv e5d4 f3d4 d7e5
info depth 4 seldepth 15 score cp -2 time 31 nodes 2307 pv e5d4 f3d4 d7e5 d3e2
info depth 5 seldepth 16 score cp 0 time 37 nodes 5527 pv e5d4 f3d4 d7e5 d3e2 c8d7
info depth 6 seldepth 21 score cp 0 time 51 nodes 11943 pv e5d4 f3d4 d7c5 d4f5 c8f5 e4f5 c5d3
info depth 7 seldepth 24 score cp 0 time 113 nodes 39051 pv e5d4 f3d4 d7c5 d4f5 c8f5 e4f5 c5d3 d1d3
info depth 8 seldepth 26 score cp 0 time 185 nodes 75908 pv e5d4 f3d4 d7c5 d4f5 c8f5 e4f5 c5d3 d1d3
info depth 9 seldepth 29 score cp -5 time 520 nodes 231590 pv e5d4 f3d4 d7c5 d3c2 a7a6 h2h3 c8d7 c1e3 f8e8
info depth 10 seldepth 33 score cp -5 time 1176 nodes 537009 pv e5d4 f3d4 d7c5 d3c2 f8e8 h2h3 c8d7 a2a3
info depth 11 seldepth 36 score cp -5 time 7098 nodes 3234342 pv f8e8 c1e3 e5d4 f3d4 d7e5 d3e2 c8g4
info depth 12 seldepth 38 score cp -5 time 11830 nodes 5379276 pv f8e8 c1e3 e5d4 f3d4 d7e5 d3e2 c8g4 e2g4 f6g4 c3d5 g4e3 d5e3 e5c4
info depth 13 seldepth 43 score cp -5 time 17509 nodes 8073171 pv f8e8 c1e3 e5d4 f3d4 d7e5 d3e2 c8g4 e2g4 f6g4 e3f4 e7f6 d1b3 a8b8
info depth 14 seldepth 47 score cp -7 time 45809 nodes 20691190 pv f8e8 d3e2 e5d4 f3d4 e7f8 d1c2 d7c5 e2f3 c8g4 f3g4 f6g4 c1e3 g4e3 f2e3
info score cp -7
bestmove f8e8

[Henk]

Rf8-e8 is not correct for white plays d4-d5 and black's position is cramped.

[flok]

White plays? Both fen strings are for black.

[MahmoudUthman]

White plays? Both fen strings are for black.

White's turn after your move "f8e8"

[PK]

in the second one I'd play ...c6. Then there is a funny plan of ...Qe8 and ...Bd8-b6. It works in normal Old Indian Defense setups (with white Bishop on e2), and here it should be even more effective.

[Dann Corbit]

[d] 3rrbk1/2qb1ppp/p1pp1nn1/1p6/2PNPP2/1PNQ3P/PB4P1/1B2RR1K b - - 0 1

Best move for black b4!!

My SF agrees with your move choice here:
[d]3rrbk1/2qb1ppp/p1pp1nn1/1p6/2PNPP2/1PNQ3P/PB4P1/1B2RR1K b - - acd 40; acs 1693; bm b4; ce 0; pm b4; pv b4 Nd1 d5 cxd5 c5 Qc2 Nxe4 Rxe4 Rxe4 Qxe4 cxd4 Bd3 Bb5 Bxb5 axb5 Qxd4 f6 f5 Bc5 Qe4 Ne7 Qe6+ Kf8 Bxf6 gxf6 Qxf6+ Kg8 Qe6+ Kh8 Qf6+ Kg8;

b4 is picked from iteration 31 forwards.

[d] r1bq1rk1/pppnbppp/3p1n2/4p3/2PPP3/2NB1N2/PP3PPP/R1BQ1RK1 b - - 4 7

Best move for black e5xd4!

I have my doubts about exd4.

Some analysis records for this second position:
SF chooses c6:
[d]r1bq1rk1/pppnbppp/3p1n2/4p3/2PPP3/2NB1N2/PP3PPP/R1BQ1RK1 b - - acd 37; acs 1296; bm c6; ce -45; pm c6; pv c6 h3 a6 d5 cxd5 cxd5 Nc5 Bc2 Qc7 Be3 Bd7 Rc1 a5 Nd2 b5 a4 Rfb8 Nxb5 Bxb5 axb5 Rxb5 b3 Rb4 Qf3 Nfd7 Ra1 Qd8 Rfb1 h6 Qe2 Bg5 Bxg5 Qxg5 Nc4 Nb7 Qf3 Qf6 Qc3 Rc8 Qg3 Nb6;

Other analysis output:
Re8:
[d]r1bq1rk1/pppnbppp/3p1n2/4p3/2PPP3/2NB1N2/PP3PPP/R1BQ1RK1 b - - acd 35; bm Re8; ce -41; pm Re8; pv Re8 b3 Nf8 h3 Ng6 Be3 h6 Nd5 Bd7 Rc1 Rc8 a4 c6 Nxe7+ Qxe7 Re1 Qd8 Bd2 c5 d5 Nh5 Bf1 Nhf4 Qc2 Nh4 Nxh4 Qxh4 Re3 Rf8 Rf3 f5 Bxf4 exf4 Re1 fxe4 Qxe4 Qf6;

exd4:
[d]r1bq1rk1/pppnbppp/3p1n2/4p3/2PPP3/2NB1N2/PP3PPP/R1BQ1RK1 b - - acd 28; bm exd4; ce -58; pm exd4; pv exd4 Nxd4 Re8 Be2 Nc5 f3 a5 Be3 g6 Qd2 Bf8 Rad1 Bg7 b3 b6 a3 Qe7 b4 Ne6 Nxe6 Qxe6 c5 axb4 axb4 dxc5 bxc5 bxc5 Bxc5 Nd7 Be3;
Notice the poor score. The move exd4 was abandoned at ply 29.

I don't have enough games to know statistically which move is superior.
But the SF analysis makes me suspect that exd4 is not the best move.

[Henk]

Nimzowitch wrote ed4:! but he may be wrong although I suspect Petrosjan learned much from Nimzowitsch. It is all about positional play. A weakness of Computer Chess. Nimzowitsch wrote Re8 was not good.

[PK]

Nimzowitsch wrote it in the days way before the rise of King's Indian defence, which learned people a lot about merits and demerits of exd4 in broadly similar positions. His idea was perfectly reasonable, as he looked at the position without much of today's pattern knowledge.