Chess – Fully Playable Board Game

Interactive Chess

Overview

This map recreates the centuries-old board game of chess inside Counter-Strike 2.

Two players can play chess on a fully physical 3D board, following the complete standard ruleset. Pieces are animated, moves are validated in real time, and the game can be played casually or with optional time controls.

A built-in computer opponent is available with adjustable strength. All gameplay logic runs entirely inside the map. No external servers, plugins, or mods are required.

Note: The computer opponent runs synchronously inside the Source 2 scripting environment. At higher strengths, move calculation will cause frame hitches / lag. The map is mostly intended for play at lower strength or between two human players.

Features

• Complete chess ruleset: legal move validation, check, checkmate, stalemate

• Special rules fully supported: castling, en passant, pawn promotion

• Physical 3D chessboard with animated piece movement and captures

• Human vs Human, Human vs Computer, or Computer vs Computer

• Adjustable computer strength (Easy / Medium / Hard)

• Optional legal-move highlighting and last-move highlighting

• Interactive on-board promotion selection (Queen, Rook, Bishop, Knight)

• Optional time control with presets and custom base / increment values

• Time control presets: Blitz 5+3, Rapid 10+0, Rapid 15+10

• Spectator support with distributed spectator spawn positions

• FEN is printed to the server console on every move (live position)

• PGN is printed to the server console at game end (can be pasted into Lichess to analyze)

How to Play

Before the Match

• In the lobby, use buttons by shooting them or pressing them with your interaction key (usually E).

• Choose a side using the join buttons.

• To play against a friend, have them select the other color.

• To play against the Engine, enable it in the Engine settings and select a difficulty.

• Shoot the start button to begin the match.

• To abort a game or play another one, return to the lobby and use the reset button.

During the Match

• Left click a piece to select it.

• Left click a target square to move.

• Right click to cancel a selection. You can also cancel a selection by left clicking the same square again.

Starting Conditions

• With the computer OFF: the match requires 2 players (White + Black).

• With the computer ON: you can start with 1 player (engine fills the other side) or even 0 players (engine vs engine).

Computer Opponent

The computer opponent evaluates positions using a compact embedded chess engine.

Engine Strength (Estimated Elo)

Approximate over-the-board strength, judged by a 2000-rated FIDE player:

• Easy - ~600 Elo

• Medium - ~1000 Elo

• Hard - ~1200 Elo

Special Thanks

This project builds on the following open-source chess projects:

chess.js by Jeff Hlywa
GitHub – chess.js repository
chess.js documentation

P4wn Chess Engine
P4wn engine homepage

Chess Pieces by Aitordsgn Sketchfab – Chess Pieces by Aitordsgn

Akiba Rubinstein and Georg Rotlewi For playing Rubinstein's Immortal, used in the thumbnail image as the position. Rubinstein's Immortal