# turncoat
A minimalistic bitboard based UCI chess engine written in Haskell with a strong focus on a clear and modular implementation with adequate performance when compared with other open source engines.
It relies heavily on GHC as well as strictness annotations in order to optimize a high level program that leverages laziness in key areas (such as staged move generation and ordering) producing an efficient binary that can compete in a field where lower level languages (C, C++, Rust) are usually employed.
Turncoat has an official account on Lichess: https://lichess.org/@/TurncoatEngine
## Characteristics
### Move Generation
- Legal Move Generation
- Specialized Static Exchanges Move Generator
- Staged Move Generation (captures & promotions, quiet moves)
### Search
- Negamax
- Alpha Beta Pruning
- Principal Variation Search
- Quiescence Search
- Iterative Deepening
- Transposition Table
- Null Move Pruning
- Futility Pruning
- Check Extensions
- Single move extensions
- Late Move Reductions
### Move Ordering
- Staged Move Ordering
- Static Exchange Evaluation
- Killer Moves
- Static Evaluation Ordering (for quiet moves)
### Evaluation
- Hand Tuned Evaluation
- Tapered Evaluation
- Material
- Piece Square Tables
- King Safety
- Mobility
- Passed Pawns
- Pawn King Shield
- Isolated & Doubled Pawns
- Knight Outposts
- Bishop Pair
- Rooks on Open Files
- Piece Threats