JESTER, the strongest pure java chess program

Important :
Jester is not a freeware. It's a Helpware. For more informations about the Helpware Operation, please read the readme.txt file included in the download package.
The author grants you the right to enjoy Jester for a private use only.
If you want to reuse or/and to publish Jester on a web site, please contact the author ( ) for the terms and conditions of reusing Jester.

Quick start :

  • Set Jester's play time (or use default settings) :

  • - number of seconds per move, or
    - number of minutes per game, or
    - K.O. game in minutes with/without bonus time per move (not avalaible)
  • Select side color for Jester.
  • Then click [New Game] button to start a new game.
  • To play a move, click the piece to move and click the destination square.
  • Important : after loaded, Jester is playable without connection (offline mode)
Options :
  • "Spy" mode :

  • Enabled : View Jester's thought.
  • "Turbo" mode :

  • Enabled : Jester will use hash-table for playing - as possible -  a best game.
  • Hide white & black pieces :

  • These options allow you to play a half or full-blindfold game.
  • Variations of chess game :

  • - Classic game : the normal chess game.

    - Fantasy game : like as classic game, but sometimes Jester plays a strange, an unexpected  move (not really the best move) which completely baffles you and "puts fire on board".

    - Clownish game : like as classic game, but when Jester gets a decisive advantage, he'll play a very bad move giving you a chance to survive.

    - One-Step-Beyond : white pawns are on the 3rd row, black pawns on the 6th row. Not available in tiny version.

    - Vaureal Dawn : knights & bishops switch their initial position on board. Not available in tiny version.

    - Crazy Horses : bishops are replaced by knights. Not available in tiny version.

    - Lethal Amazones : knights & bishops are replaced by queens. Not available in tiny version.

    - Throne of chaos : like as Fischerandom game. Not available in tiny version.
  • Edit mode :

  • - Click [Modification] button to enter in edit mode. Select a piece with [Select Piece] button and click on the square to place a new piece. When all done, click again [Modification] button to leave edit mode.
    Then, click [New game] button to start a game with the new position. White side always plays first.
Other buttons :
  • Oops! :

  • Take bake last player move. Not allowed in K.O. game.
    Warning: sometimes Jester cheats if you abuse this button !
  • Exit :

  • Exit Jester.