Emerald 0.4.0 - new version chess engine

 

Emerald - UCI chess engine

Author: Zhongle Qu

Emerald 0.4.0 - what's new?

A full rewrite of search algorithms. Fixed bugs and now (finally!) correctly works with history & killer heuristics.

An update to the MovePicker class. Now it won't generate all moves at once, making the engine even faster.

A brand-new NNUE for evaluation. Please find more details in README.

Performance:

Beats previous version with around 91% win rate (i.e. roughly +402 Elo improvement).

Against other opponents:

Opponent Version CCRL Blitz Elo Elo difference

Neuromancer 1.5 1828 +173

Cadabra 2.0.0 1960 +155

Lynx 0.16.0 1970 +250

Blunder 5.0.0 2014 +200

Stash 15.3 2170 +61

Oxide 1.0.0 2238 -264

Estimated Elo: 2100 2211 +/- 20 CCRL blitz scale

All games tested under 10+0.1 time control; played 60 games against each opponent (so the results are not necessarily reliable; the actual outcome may be quite different).

Emerald 0.3.0 JA vs other engines:

Mister Queen 1.0 JA	1.5/4	-1	4 Games
Freda 1.1 JA	1/4	-2	4 Games
PZChessBot 2.0 JA	0/4	-4	4 Games
Meltdown 1.8 JA	0/4	-4	4 Games
Razer 0.0 JA	0/4	-4	4 Games
Fridolin 4.00 JA	0/4	-4	4 Games
Ironfang 1.0	2/2	+2	2 Games
Rustyrook 110 JA	1.5/2	+1	2 Games
Critter 1.6a	0/2	-2	2 Games
Aku 2025.22.5 JA	0/2	-2	2 Games
Fire 9.3 JA	0/2	-2	2 Games
PlentyChess 6.0.5 JA	0/2	-2	2 Games
Kraken 2025-06-16	0/2	-2	2 Games
Stormphrax 7.0.0	0/2	-2	2 Games
Aku 2025.6.12	0/2	-2	2 Games
Iris 1.0 JA	0/2	-2	2 Games
Mayhem 8.8 JA	0/2	-2	2 Games
Obsidian dev-16.08	0/2	-2	2 Games
Pawnocchio 1.7.2	0/2	-2	2 Games
Publius 0.063 JA	0/2	-2	2 Games
RubiChess 20250606 JA	0/2	-2	2 Games

Emerald 0.4.0 download