Berserk Chess Engine

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

Elo History

CCRL (40/15)

Rank #13

Version	Elo	TC
3.2.1	2935	40/15
4.2.0	3131	40/15
4.2.0 (4CPU)	3224	40/15
4.5.1	3294	40/15

CCRL (Blitz)

Rank #16

Version	Elo	TC
1.2.2	2160	2'+1"
2.0.0	2546	2'+1"
3.2.0	2896	2'+1"
4.1.0	3117	2'+1"
4.4.0	3316	2'+1"
4.4.0 (8CPU)	3467	2'+1"

Lars No SMP

Rank #10

Version	Elo	TC
2.0.0	~2600	15'
3.0.0	2818	15'
3.2.0	2901	15'
4.0.0	3027	15'
4.1.0	3085	15'
4.2.0	3143	15'
4.3.0	3248	15'
4.4.0	3314	15'
4.5.0	3344	15'

Features

Board Representation and Move Generation

• Bitboards
  • In combiniation with Magic bitboards
• Legal Move Gen
  • It is Staged

Search

• Negamax and Quiescence
• PVS
• Transposition Table
• Iterative Deepening
• Aspiration Windows
• Null Move Pruning
• Delta Pruning
• Reverse Futility Pruning
• LMR
• MVV-LVA
• SEE
• Killer Heuristic
• Countermove Heuristic
• Extensions
  • Singular
  • Check
  • Recapture
  • History
  • Castle

Evaluation

• Tapered
• Material
• Piece Square Tables
• Mobility
• Pawn Structure
• King Safety
• Space
• Piece Imbalance
• Texel Tuned

Future Improvements

• FRC Support
• Small Pawn NN
• Piece specific EG evaluation methods
  • Potentially small NNs for these
• Proper KS Tuning

Building

At this time Berserk only supports gcc

$ git clone https://github.com/jhonnold/berserk
$ cd src
$ make
$ ./berserk

Credit

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

Engine Influences

• chess22k
• bbc
  • youtube
• Martin Sedlak
  • Very nice and helpful in later development of Berserk
• Vice
• Weiss
• Stockfish
• Ethereal
  • This has been especially helpful as it introduced me to OpenBench
• CPW

Additional Resources

• Open Bench
• TalkChess Forum
• CCRL
• JCER
• Cute Chess
• Arena
• Lars in Graham's CCRL rooms for a nice engine list
• Koivisto authors for advice and assistance on OpenBench