The Catto Chess Engine

Play Catto

If you just want to play or use Catto, you can download the engine in the releases page and import it into a chess GUI (e.g. Arena, Cute Chess or Lucas Chess).

If you want to use Catto for development, follow the steps below.

Dependencies

• Node.js & npm

Note that you may also want to use Bun which is a much faster JS runtime env than Node.js.

Setup

1. Clone the repository to your machine.

2. Go to ./Catto/, install the packages:

npm install

3. Compile Catto:

npx tsc

4. Fire up Catto!

node .

Build into executable

In your console, type:

npm run build

If you are using Bun:

npm run bun-build

Configure

There are several configurations for Catto that you can change in catto.config.js if you want:

module.exports = {
    // Current version to show in UCI
    version: "v0.7.0",
    // Late move reduction config
    lmrFullDepth: 4, // Number of moves to be searched in full depth
    lmrMaxReduction: 3, // Only apply LMR above this depth
    // Search extensions config
    maxExtensions: 2 // Seach extension limit
}

Note that the config file is compiled with the engine itself, so if you are using the built version, like catto.exe, creating a catto.config.js file will have no effect.

What do we currently have?

The engine

• Principle variation search.
• Move ordering:
  • Hash move ordering.
  • PV move ordering.
  • MVV-LVA heuristic.
  • Killer heuristic.
  • History heuristic.
  • Countermove heuristic.
• Transposition table.
• Pruning:
  • Reverse futility pruning.
  • Null-move pruning.
  • Razoring.
  • Futility pruning.
  • Delta pruning.
• Late move reductions.
• Search extensions:
  • Check extensions.
  • One reply extensions.
• Quiescence search.
• Iterative deepening.
• Aspiration windows.
• Time control:
  • Fixed time per move: 1/30 of the remaining time.
• Evalution:
  • PeSTO evaluation (PST, materials, and tapered evaluation).
  • Isolated, doubled and passed pawns bonus/penalty.
  • Mobility:
    • Rook on open/half-open file bonus.
    • Bishop legal moves.
    • Queen legal moves.
  • King safety:
    • Penalty if king is on half-open file.
    • Bonus if king has pieces nearby.
• UCI.

Todos

See todos for Catto here.

Copyrights

Copyrights © 2024 Nguyen Phu Minh.

This project is licensed under the GPL-3.0 License.