babak-ssh / kojiro

A simple UCI Chess Engine

Kojiro

An UCI-compatible Chess Engine written in C++

Description

Kojiro is a free, UCI chess engine written from scratch in C++,which i have developed for fun and to learn about chess programming, it uses well-known concepts used in chess programming for many decades and a lot of ideas are taken from chessprogramming wiki and talk chess forum and open-source engines.

Features

• Search:
  • AlphaBeta Pruning
  • Aspiration Window
  • Iterative Deepening
  • Null Move Pruning
  • Razoring
  • Late Move Reductions
  • Quiescence Search
  • Multi Threads(Lazy SMP)
• Move Ordering:
  • Hash Move
  • TT Move
  • MVV/LVA
  • Killer heuristic
  • History heuristic
• Evaluation:
  • Evaluation Tapering
  • Piece Square Tables
  • Pawn Structure
  • Piece Mobility
  • Open Files
• Other:
  • Zobrist Hashing
  • Transposition Table
  • logging
  • UCI

Usage

you can use UCI protocol by running the main file or use an UCI-compatible graphical user interface(GUI) (e.g. Arena, Sigma Chess) in order to be used comfortably.

also you can challenge it on Lichess! --> https://lichess.org/@/tha_kojiro

Compiling Kojiro

to compile the engine use:

cd src
make kojiro
./kojiro

Tests

to compile perft tests

cd src
make perft

usage:

./perft depth fen
./perft 5 rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

inspiring open-source chess-engines:

• BBC by Maksim Korzh
• Stockfish by Tord Romstad, Joona Kiiski, Gary Linscott, Marco Costalba
• Rustic by Marcel Vanthoor
• Vice by BlueFeverSoft

Kojiro is still under develop

there are many techniques and features that will be added:

• use more modern cpp features to enhance the performance
• better evalution
  • pawn (push, shield)
  • center control, castling
  • piece pair, blocked pieces
• more tests
• futility prunning (in alpha-beta and quiescence)
• time distribution model for time management of moves
• opening books
• Syzygy support
• NNUE
• internal iterative deepening
• better sorting
  • Counter
  • LastCaptureBonus
  • SEE
  • Checks priority
  • En-passant priority
• Xboard protocol
• windows support
• wiki