Berserk Chess Engine

<img src="resources/berserk.jpg" alt="Berserk" width="400" />

A UCI chess engine written in C. Feel free to challenge me on Lichess!

Strength

Rating Lists + Elo

Many websites use an Elo rating system to present relative skill amongst engines. Below is a list of many chess engine lists throughout the web (variance in Elo is due to different conditions for each list)

• CCRL 40/15 - 3514 4CPU, 3480 1CPU
• CCRL 40/2 - 3667 1CPU
• IpMan Chess - 3547 1CPU
• CEGT - 3598 1CPU
• SPCC - 3733 1CPU
• ~~FGRL - 3518 1CPU~~
  • List no longer maintained

Tournaments/Events with Berserk

• TCEC
• CCC
• Graham's Broadcasts

Functional Details

Board Representation and Move Generation

• Bitboards
  • Magic Bitboards
• Staged Move Gen

Search

• Negamax
  • PVS
• Quiescence
• Iterative Deepening
• Transposition Table
• Aspiration Windows
• Internal Iterative Reductions
• Reverse Futility Pruning
• Razoring
• Null Move Pruning
• ProbCut
• FutilityPruning
  • LMP
• History Pruning
• SEE
  • Static Exchange Evaluation Pruning
• LMR
• Killer Heuristic
• Countermove Heuristic
• Extensions
  • Singular

Evaluation

• NNUE
  • Horizontally Mirrored 16 Buckets
  • 2x(12288 -> 512) -> 1
• Berserk FenGen
• Grapheus
• ~~Koivisto's CUDA Trainer~~
  • This has been deprecated in favor of an even newer trainer written by Luecx, Grapheus.
• ~~Berserk Trainer~~
  • This has been deprecated in favor of Koivisto's trainer, but trained all networks through Berserk 8.5.1+

Building

git clone https://github.com/jhonnold/berserk && \
cd berserk/src && \
make pgo CC=clang && \
./berserk

Credit

This engine could not be written without some influence and they are...

Engine Influences

• Stockfish
• Ethereal
• Koivisto
• Weiss
• Chess22k
• BBC
• Cheng

Additional Resources

• Grapheus
• Koivisto's CUDA Trainer
• OpenBench
• TalkChess Forum
• CCRL
• JCER
• Cute Chess
• Arena
• CPW
• Lars in Grahams Broadcast rooms