Medita Chess

Medita chess is a chess game that runs as either a Java applet or as an Android app. The Java engine is identical in both versions, although the Android version has a lower default playing strength due to the reduced power of phones/tablets compared with a desktop PC.

Features:

Play against computer, or watch computer play itself.
Play as white or black (with option to invert board)
The playing strength can be adjusted at any point by dragging the slider. This adjusts the number of moves the computer will look ahead. I recommend using values of around 4-6 on a desktop PC and 2-4 if running on a phone/tablet.
Displays moves searched and the number of moves per second
Opening book with all ECO openings
Most chess rules implemented including castling, en-passant, pawn promotion
Undo move
Pondering - program thinks during opponent's move
Practice any ECO opening with each move highlighted
Save and load game position
Analyze position using "Analyze This" app (needs to be installed separately)