The changes are:
- More aggressive pruning in search.
- Increased value of rook vs. minor and pawns if both sides have pawns.
- Improved handling of king and queen vs. king and rook.
- Compressed the bitbase for king and pawn vs. king from 32 kB to 24 kB.
- The mate searching mode is about 30% faster.
- More opening book knowledge.
- Improved protection against false opening book hits.
- Added option for aggregate castling rights in the position editor of the microcontroller version.
Here are two games of V1.40 (microcontroller version) vs. Mephisto Berlin Pro London (68020, 24 MHz), both at 30 minutes per game. The CT800 without overclocking.
The CT800 with Black opts for Modern Defence, and the BLP goes for the f2-f4 attack. The CT800 holds its ground and undermines White's pawn centre as intended. White doesn't get around to castling, but Black's king position isn't exactly a low-energy house, either. At the end of a wild game where both sides overlook possible advantages, the BLP heads for draw by threefold repetition through perpetual check.
In the rematch, the CT800 has White and chooses the pretty rare f2-f3 side variant of the Trompovsky attack, still from the embedded opening book. White castles long, Black short. White unleashes a pawn storm. The BLP, losing ground, tries a centre pawn sacrifice to get some counterplay, but White's attack is already too strong. A queen exchange lets Black fend off mate, but not the white passed pawns, and the BLP resigns.
That were the first two test games of V1.40, and not only that the CT800 has reached its first draw against the BLP, but even a win.
[pgn]
[Date "2020.04.04"]
[White "Mephisto Berlin London Pro"]
[Black "CT800"]
[WhiteElo "2281"]
[TimeControl "1800"]
[ECO "B06"]
[Result "1/2-1/2"]
1. e4 g6 2. d4 d6 3. Nc3 Bg7 4. f4 Nc6 5. Nf3 Bg4 6. Bb5
Bxf3 7. gxf3 a6 8. Bxc6+ bxc6 9. Be3 Rb8 10. Rb1 Nf6
11. Rg1 O-O 12. f5 e6 13. fxe6 fxe6 14. Bg5 Qe8 15. Qd3 Nd7
16. Ne2 c5 17. c3 cxd4 18. cxd4 c5 19. Qxa6 cxd4 20. Qxd6
Be5 21. Qa3 Ra8 22. Qb3 Bxh2 23. Rg2 Be5 24. Rd1 Qf7 25. f4
Rfb8 26. Qh3 Bg7 27. Nxd4 Nc5 28. b3 Nxe4 29. Re2 Nc5
30. Nc6 Rb5 31. Rh2 h5 32. Rd8+ Rxd8 33. Nxd8 Qe8 34. Qe3
e5 35. a4 Rxb3 36. Qxc5 exf4+ 37. Be7 Bc3+ 38. Kf1 Rb1+
39. Kg2 Rb2+ 40. Kh1 Rb1+ 41. Kg2 Qd7 42. Qc4+ Kh7 43. Qf7+
Bg7 44. Rxh5+ gxh5 45. Qxh5+ Kg8 46. Qf7+ Kh7 47. Qh5+ Bh6
48. Qf7+ Bg7 49. Qh5+ 1/2-1/2
[/pgn]
[pgn]
[Date "2020.04.04"]
[White "CT800"]
[Black "Mephisto Berlin London Pro"]
[BlackElo "2281"]
[TimeControl "1800"]
[ECO "A45"]
[Result "1-0"]
1. d4 Nf6 2. Bg5 Ne4 3. Bf4 d5 4. f3 Nf6 5. Nc3 Bf5 6. Qd2
e6 7. O-O-O Bb4 8. g4 Bg6 9. h4 h6 10. h5 Bh7 11. a3 Ba5
12. Nh3 O-O 13. e3 c5 14. dxc5 Nc6 15. g5 d4 16. exd4 Bxc3
17. Qxc3 Nd5 18. Qd2 Nxf4 19. Qxf4 e5 20. dxe5 Qe7 21. gxh6
Qxc5 22. Bc4 Qxe5 23. Rhg1 Qxf4+ 24. Nxf4 Rfd8 25. Rxd8+
Rxd8 26. hxg7 Nd4 27. Bd5 Rxd5 28. Nxd5 Ne2+ 29. Kd2 Nxg1
30. h6 f5 31. Nf6+ Kf7 32. Nxh7 Nxf3+ 33. Kd1 f4 1-0
[/pgn]
