FollyChess

       ,,
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     / 'O  |
    (   < _|
     \___/
     /   \
    /_____\
   /_______\
   (________)

   FollyChess

FollyChess is a UCI-compatible chess engine written in C++23.

Getting Started

Prerequisites

Ensure your environment is set up with the following:

1. A C++23 compiler such as Clang 17+.

2. Bazel.

Compiling

To build the optimized UCI command-line interface, run:

bazel build --compilation_mode=opt //cli:follychess

The binary will be written to bazel-bin/cli/follychess.

Usage

Using with a GUI (Recommended)

To play against FollyChess, install a UCI-compatible GUI such as:

• Arena
• BanksiaGUI
• Cutechess
• HIARCS Chess Explorer

Configure the GUI to point to the bazel-bin/cli/follychess executable.

Running via CLI

You can interact with the engine directly via standard input for debugging or scripting.

$ bazel-bin/cli/follychess

        ,,
      ,/  \
     / 'O  |
    (   < _|
     \___/
     /   \
    /_____\
   /_______\
   (________)

   FollyChess

d
8: r n b q k b n r
7: p p p p p p p p
6: . . . . . . . .
5: . . . . . . . .
4: . . . . . . . .
3: . . . . . . . .
2: P P P P P P P P
1: R N B Q K B N R
   a b c d e f g h

   w KQkq - 0 1

position startpos moves e2e4 e7e5
d
8: r n b q k b n r
7: p p p p . p p p
6: . . . . . . . .
5: . . . . p . . .
4: . . . . P . . .
3: . . . . . . . .
2: P P P P . P P P
1: R N B Q K B N R
   a b c d e f g h

   w KQkq e6 2 2

Development

The project includes several helper scripts for development and testing.

Script	Description	Example
benchmark	Runs a single benchmark and updates the results in the benchmarks directory.	./benchmark attacks
perft	Runs all Perft tests to verify move generation.	./perft
watch	Watches the directory for file changes. Automatically recompiles (fastbuild) and runs unit tests on save.	./watch

Running Tests Manually

If you prefer not to use the watch script, you can run tests directly via Bazel:

bazel test //...