Berserk Chess Engine

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

Elo History

CCRL (40/15)

Rank #5

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
6	3327	40/15
6 (4CPU)	3395	40/15
7	3387	40/15
7 (4CPU)	3435	40/15
8	3399	40/15
8 (4CPU)	3453	40/15
8.5.1	3422	40/15
8.5.1 (4CPU)	3467	40/15
9	3434	40/15
9 (4CPU)	3472	40/15

CCRL (Blitz)

Rank #7

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"
6	3436	2'+1"
6 (8CPU)	3559	2'+1"
7	3488	2'+1"
7 (8CPU)	3600	2'+1"
8	3518	2'+1"
8 (8CPU)	3626	2'+1"
8.5.1	3540	2'+1"
8.5.1 (8CPU)	3638	2'+1"
9	3589	2'+1"
9 (8 CPU)	3667	2'+1"

Lars No SMP

Rank #2

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'
5	3371	15'
6	3446	15'
9	3619	15'

Other Lists with Berserk

• Ipman Chess
• CEGT
• Stefan Pohl Computer Chess
• FGRL
• Gambit Rating List

Events with Berserk

• TCEC
• CCC
• Graham's Broadcasts

Funcational 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
  • Check
  • Recapture
  • History

Evaluation

• NNUE
  • Horizontally Mirrored 8 Buckets
  • 2x(6144 -> 512) -> 1
• Berserk FenGen
• Koivisto's CUDA Trainer
• 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 basic
$ ./berserk

Credit

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

Engine Influences

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

Additional Resources

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