Hi community!
This is joined topic for VeryChess chess engine releases for all versions 0.x (everything until 1.0).
The last version published here was VeryChess 0.4.0 - viewtopic.php?p=996188
VeryChess 0.6.0 - released 11 August 2026
This is an evaluation and search-quality release.
The entire hand-crafted evaluation was automatically tuned with a Texel-style optimizer built for this release, and two pawn-evaluation terms were re-introduced as jointly-tuned features. Also it adds two standard selective-pruning techniques to the main search.
Together these are worth roughly +300 Elo in self-play against VeryChess 0.4.0 at fast time control.
VeryChess 0.7.0 - released 21 August 2026
This is primarily a search release. Its headline is singular extensions: the engine detects when the transposition-table move is clearly better than every alternative and searches that move one ply deeper, sharpening tactics and forced lines. It also retunes king safety for a small further gain, fixes the evaluation of a few known-drawn endgames, adds a go nodes search limit, and — importantly — fixes a search-robustness bug where some positions could ignore the move-time limit and never return a move.
Together these are worth roughly +34 Elo in self-play against VeryChess 0.6.0 at a long time control.
VeryChess 0.8.0 - released 2 September 2026
This release makes the engine both stronger and — by a wide margin — faster. Three changes each add roughly twenty to thirty Elo: a clustered transposition table, internal iterative reduction, and a fix to how pinned pieces are evaluated. Separately, the search itself now runs about 2.7× faster than 0.7.0 did, mostly because sliding-piece attacks are now magic bitboards instead of a step-by-step ray walk, and because the macOS build was discovered to have been running emulated. Windows users now get two binaries to choose from.
VeryChess 0.9.0 - released 13 September 2026
Release page - https://verychess.org/releases.html
Direct download - https://verychess.org/download/verychess0.9.0.zip
This release is about search quality and cost. Two changes add strength outright — aspiration windows (+27.9 Elo) and a transposition table in quiescence search (+9.5 Elo) — while three more make the engine do substantially less work for the same playing strength: staged move generation halves the moves generated per node, a negative extension cuts the tree by a further 16%, and a large internal cleanup drops per-thread memory by 92%. The engine also gains exact endgame knowledge (a KPK bitbase and a KBNvK mating technique) that needs no external files.
In the roundrobin tournament with older versions VeryChess 0.9.0 shows significant increasing strength:
Code: Select all
Result:
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# name games wins draws losses score elo + -
1. VeryChess 0.9.0 200 121 74 5 158.0 325 36 34
2. VeryChess 0.8.0 200 74 93 33 120.5 217 32 31
3. VeryChess 0.7.0 200 53 85 62 95.5 153 32 32
4. VeryChess 0.6.0 200 39 86 75 82.0 115 32 32
5. VeryChess 0.5.0 200 14 60 126 44.0 0 35 37
Cross table:
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# name score games 1 2 3 4 5
1. VeryChess 0.9.0 158.0 200 x 35.0 40.5 42.0 40.5
2. VeryChess 0.8.0 120.5 200 15.0 x 29.0 35.0 41.5
3. VeryChess 0.7.0 95.5 200 9.5 21.0 x 29.0 36.0
4. VeryChess 0.6.0 82.0 200 8.0 15.0 21.0 x 38.0
5. VeryChess 0.5.0 44.0 200 9.5 8.5 14.0 12.0 x
Tech:
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Tech (average nodes, depths, time/m per move, others per game), counted for computing moves only, ignored moves with zero nodes:
# name nodes/m NPS depth/m time/m moves time
1. VeryChess 0.9.0 12185K 3483641 21.9 3.5 65.9 230.4
2. VeryChess 0.8.0 15474K 3977356 20.5 3.9 63.2 245.9
3. VeryChess 0.7.0 7895K 2040738 18.9 3.9 65.2 252.2
4. VeryChess 0.6.0 6262K 1591914 20.3 3.9 62.2 244.7
5. VeryChess 0.5.0 6108K 1558761 20.4 3.9 69.2 271.2
all --- 9318K 2497333 20.4 3.8 65.1 248.9