Slate ChessSlate engine
A free UCI chess engine, written from scratch in Swift. The engine behind the Slate Chess app.
Downloads (0.5.3, released 3 November 2026)
| Platform | Needs | File | SHA-256 |
|---|---|---|---|
| Linux x86-64 (any CPU) | glibc 2.35 or later (Ubuntu 22.04+, Debian 12+, Fedora 36+) | slate-0.5.3-public-linux-x86-64.zip | 1ae45871d71afe19e9167f47a266f1594725b95b3ecbe6210c3c6af1b200fc05 |
| Linux x86-64, AVX2 (CPUs from 2013 on) | glibc 2.35 or later, and an AVX2 CPU (2013 on) | slate-0.5.3-public-linux-x86-64-haswell.zip | 45ca4970d03165b056fa22338020b42c6e2470eda562058fa3d76732500ed7c1 |
| Linux arm64 | glibc 2.35 or later (Ubuntu 22.04+, Debian 12+, Fedora 36+) | slate-0.5.3-public-linux-arm64.zip | d7256f8e328de8e6cacf89374e792f8148389381bee9fe24cb3ebbdf4b316888 |
| macOS, Apple silicon | Apple silicon, macOS 15 or later If it won't open | slate-0.5.3-public-macos-arm64.zip | ee9930e8733c1953a15892a95edb2632afcb2d53c948dca4d4709603d966ec76 |
| Windows x86-64 | 64-bit Windows 10 or 11 (x86-64). Needs Microsoft's Visual C++ runtime, already on most PCs (otherwise install Microsoft's Visual C++ Redistributable, x64). If Windows warns you | slate-0.5.3-public-windows-x86-64.zip | 3706a117280daadecf175e7b3606d674bf14b05c9bb2d81942fa82e5b42fde2c |
Before you run it. The engine isn't signed yet: the Mac build isn't notarized by Apple and the Windows build isn't code-signed, so your computer may warn you the first time you run it. On a Mac, the fix is one command or one click. On Windows, if you see "Windows protected your PC", choose More info, then Run anyway. Check the SHA-256 hash above first. We plan to notarize and sign future releases.
All hashes in one file: SHA256SUMS.txt.
Licence
Free for personal use, analysis, engine testing and rating lists. You may publish results and games, and pass on unmodified copies for those purposes. Embedding Slate in another product or service, commercial redistribution, and modifying or reverse-engineering it need written permission. Full licence.
Using it
Slate speaks standard UCI, so it should work in any UCI GUI. We test it with cutechess-cli and fastchess, the match tools rating lists use, and with Arena. Set Hash and Threads as usual. It has no opening book or tablebase support of its own; use your GUI's. Installing, options and fixes are in the UCI Engine Guide.
Strength
About 3,220 on a CCRL-like scale: our own measurement against public engines (1 thread, 10 s + 0.1 s per game, Apple M3 Max). Not an official rating list figure.
Release notes: Slate 0.5.3
Released 3 November 2026. A strength release: about 30–50 Elo stronger than 0.5.2 against other engines.
What's new
- Better piece knowledge. The evaluation now understands more about how pieces work: mobility that depends on the piece and on which squares are safe, trapped and dominated pieces, bad bishops, outposts, rooks on open and closed files, and queen safety. Every weight was re-tuned on 200,000 games the new engine played against itself.
- Correction history. The search learns, during a game, where its evaluation tends to be wrong in a given pawn structure, and corrects for it.
Measured against 0.5.2
| Measure | 0.5.2 | 0.5.3 |
|---|---|---|
| Rating on a CCRL-like scale (our own measurement: 1 thread, 10 s + 0.1 s, eight public engines, 3,200 games) | 3,202 ±14 | 3,224 ±10 |
| Gauntlet against the same engines, same openings (0.5.3 minus 0.5.2) | +29.6 ±14.9 Elo | |
| Search speed (nodes per second, 1 thread, Apple M3 Max) | 3.21 M | 2.84 M (−10%) |
The rating is our own estimate against public engines, not an official rating-list figure.
At fast time controls, down to 20 seconds plus 0.3 seconds a move, 0.5.3 lost no games on time in 960 test games.
Known limitations
- The search is about 10% slower per node, the cost of the new evaluation terms. All the strength figures above were measured on a clock, so they already include it.
- Slightly fewer endgame draws recognised (92.8% against 93.9% on our endgame test set).
Compatibility
Plain UCI. Options: Hash, Threads, MultiPV, Ponder, Move Overhead, Contempt, Clear Hash, UCI_ShowWDL, UCI_AnalyseMode, UCI_EngineAbout. No opening book or tablebase support of its own; use your GUI's. Check each download against the SHA-256 hash listed next to it.
Contact
Questions, bug reports, testing: support@slatechess.com