Free play chess software for linux

Vulcan Chess project allows you play against the computer in a chess variant inspired by a certain well-known science-fiction TV series.
Enhancements:
- Castling was added.
- The legal move generator is a bit faster.

Ruby Chess is a chess game implemented in Ruby using GTK2. Ruby Chess project has a good artificial intelligence that is heuristic-based and stochastic.

TryChess project is a multiplayer online chess game.
First it was only a test to try PHP5s news features. But it started growing and became a nearly complete chess game with many features.
Main features:
- Multiplayer game
- Preview move
- Hostory of moves
- Check and Check mate detection
- Browser indepentant (even lynx works, but does not look so good :) )
- Special moves supported partialy (rochade,...)
- Top Score list
- Invite friend function
- "Whos online?"
- Forum
- Admin functions
- Search for users

Emacs Chess is an object-oriented library written in Elisp for manipulating chess objects (games, plies, positions, etc.), and for displaying them.
Main features:
- Emacs Chess is also an object-oriented library for manipulating chess objects (games, plies, positions, etc), and for displaying them. It supports a wide range of engine objects to use as move sources. This what allows chess.el to act as a chess client.
- chess-announce.el announces your opponents moves verbally, such as "knight takes at f4"provided you have "festival" installed.
- chess-sound.el is similar to chess-announce, but uses specific WAV files for each sound used. It takes up much more disk space, but is nicer to listen to. Available in English only at the moment.
- chess-irc.el provides a tiny IRC bot, allowing you to play games over IRC so long as your opponent enters moves in short algebraic notation. If they dont have chess.el, all they need is a regular chessboard, and a knowledge of SAN (short alegebraic notation).
- chess-ics.el lets you to play on Internet Chess Servers, using chess.el as your chessboard display (which means chess-announce works with it, etc). It has only been tested with FICS so far.
- chess-crafty.el, chess-gnuchess.el and chess-phalanx.el let you play against the Crafty, Gnuchess and Phalanx engines.
- chess-random.el will create Fischer Random positions to play against. Note that this feature only really works against opponents who are also using chess.el. Simply type "S" in the chessboard display buffer to setup a Fischer Random starting position.
- chess-network.el lets you play against other chess.el users directly, over a single open port on the server side. To be a server, you must have "netcat" installed, or be using Emacs 21.3 or higher (which supports server side network sockets). To be a client, all you need is Emacs 21.1 or higher.
- chess-link.el lets you tie two engines together, so that events from one are responded to by events from another. This can let you run a chess bot on your computer over any of the transport, or you can use it to pit two computer chess engines against each other.
- chess.el can even export chessboard display to other X servers, allowing you to play against people in your meeting room, even if they dont have Emacs installed!
Enhancements:
- This maintenance release includes several bugfixes.

HellChess project is a freeware chess program that guides beginners through the game, while intermediate and expert players can evaluate their level of play and match wits with the opponent available in HellChess or online on the net.
HellChess is the first project that is using the full features of the BraatWorst engine and serves as an perfect example of the capabilities this engine can provide.
Main features:
Perfect online teaching while chatting to trainee in the game.
- Using HellChess one can give online training to students that are willing to learn chess. The teacher can setup a chessboard while chatting to the trainee. The trainee will see the chessboard being setup while the teacher is placing his pieces. This is really helpfull to both trainee and teacher. If a trainee does a bad move, the teacher can undo his move and explain why using the edit board or the chat function.
Battle between different computers
- Tired of your friends claiming their machine is better than yours ? Why not let it play against a friends computer ? You can let HellChess play against the other machine using the networking option. Whoever wins will have the better machine and youll earn respect.
Bored waiting ?
- Now you can install HellChess on your PocketPC and tickle your brain whenever you have to wait. Youll be surprised how quickly time passes when battling your pieces on the board against the CPU. And now with the new games Othello and Connect4 you can also play a different kind of game whenever youve had enough chess battles.
Enhancements:
- The game can now also play Chinese chess, Japanese chess, and Checkers.
- Built-in documentation that explains all of the game rules was included along with several tutorials for learning these games.
- The skin was changed.

pychess is a chess game written using pygtk.
Should be able to do most things xboard does, but in a nicer gtk/svg enviroment.
Will support
- Svg pieces
- Pgn reading/writing
- Animation
- DnD
- Builtin move validation
- Multiple engines
- and much more.

Brutal Chess project features full 3D graphics, an advanced particle engine, and several different levels of intelligent AI, inspired by the once popular "Battle Chess" released by Interplay circa 1988.