Raphael 3.1 - new version chess engine

Raphael is a hobby project that is still a work in progress, but it will be updated as time goes by. It is nowhere near as competitive as some of the other chess engines out there, but it is strong enough to beat most humans with ease. 

Author: Rei Meguro

Raphael 3.1 - what's new?

Non-functional changes

• uci no longer freezes when you call isready during search
• uci no longer sets internal position until isready or ucinewgame is called
• most uci commands won't run during search now (instead of stopping search to run)
• command line arguments are now parsed as uci commands (use "" for commands with spaces in them)
• added help, genfens, eval, and evalutils command to uci

v3.1

• added support for DFRC
• refactored make/unmake to copymake
• implemented NNUE horizontal mirroring
• implemented NNUE output buckets
• increased NNUE HL size to 768
• implemented these thanks to Jonathan Hallström, author of Pawnocchio
  • cutnode negex
  • lmr depth in fp

Performance

• +199 STC against v3.0 (3520 estimated CCRL blitz)
• +231 LTC against v3.0 (3428 estimated CCRL 40/15)

Bench: 10690874

Raphael 3.0.0 JA vs other engines:

Rusty-rival 1.0.30 rc3	4/4	+4	4 games
FrankyCPP 1.2	4/4	+4	4 games
Human Chess Engine 0.1 JA	4/4	+4	4 games
Anodos 1.2.0	4/4	+4	4 games
Critter 1.6a	3.5/4	+3	4 games
Chessnix 1.3	1.5/4	-1	4 games
Kociolek 2.1 JA	1.5/4	-1	4 games
PZChessBot 6.1	1/4	-2	4 games
Caligula 6.0	1/4	-2	4 games
Bagatur 5.4	1/4	-2	4 games
Minke 5.0.0	0.5/4	-3	4 games
Odonata 1.1.0	0.5/4	-3	4 games
Zangdar 6.1	0.5/4	-3	4 games
Sturddle 2.5.0	0.5/4	-3	4 games
Stockfish 18 JA	0/4	-4	4 games
DON dev-20260215	0/4	-4	4 games
Tarnished 5.0	0/4	-4	4 games
Halogen 16.0.0	0/4	-4	4 games
HypnoS EN 1.0	0/4	-4	4 games
VietCoffee 1.0.8 JA	3/3	+3	3 games
Vajra 2.0	3/3	+3	3 games

Raphael 3.1 download