Bannou

Bannou is a work-in-progress chess engine written in Zig.

UCI commands

Bannou aims to follow the Universal Chess Interface protocol, and communicates through stdin and stdout.

The following UCI commands are supported:

uci
debug [on|off]
isready
ucinewgame
go wtime <x> btime <x> winc <x> binc <x>
position [fen <fenstring> | startpos] [moves <move_1> ... <move_i>]
quit

Notably stop is not currently supported.

In addition to the above UCI commands, the following non-standard commands are supported:

d                            Print board state
move <move_1> ... <move_i>   Make move(s) from the current position
undo [<plys>]                Unmove specified number of plys of moves; defaults to depth of 1
perft [<depth>]              Divided perft to specified depth; defaults to depth of 1
bench                        Run benchmark
eval                         Evaluation of current position
history                      Display information about move history
auto [<depth>]               Equivalent to `go depth <depth>` followed by making the resulting
                             bestmove on the board; defaults to depth of 1

Feature List

• Board representation
  • 0x88 mailbox board representation
  • BCH hashing
• Search
  • Negamax search
  • Alpha-beta pruning (fail-soft)
  • Principal Variation Search
  • Aspiration windows
  • Quiesence search
  • Basic time management with soft and hard timeouts
  • Swiss-like transposition table (14-way)
  • Transposition table cutoffs
  • Null move reduction (followed by pruning on second NMR)
  • Reverse futility pruning
  • Late move reductions
  • Late move pruning
• Move ordering
  • MVV-LVA
  • Killer move heuristic
  • Counter move heuristic
  • History heuristic
• Evaluation
  • Tapered piece-square tables