Reversi, against the computer
An 8-by-8 board, with black discs on one side and white on the other. You place a disc to surround your opponent's discs, which then flip over. This site explains the rules as the app applies them and shows positions calculated by its code. Reversi pits you against the computer, at 3 levels.
On phone and tablet
Screenshots of the published app. The app is displayed in portrait, with the device held upright.
Where to start?
The rules
The start, the legal move, flips in every direction, passing, the end of the game and the final count.
Strategy
Corners, squares to avoid, edges, and why counting your discs too early is misleading.
Worked exercises
6 positions taken from a real game, with the solution.
An annotated game
All 60 moves of a game the app's computer plays against itself.
Reversi in a few lines
Players take turns placing a disc of their color on an empty square. A move is legal only if it surrounds at least one opposing disc, in a straight line, between the placed disc and another of your own discs. All the surrounded discs change color, in all 8 directions at once.
A player with no legal move passes. When nobody can move any more, whoever has the most discs wins. In the annotated game, Black leads 41 to 14 after 51 moves… and loses 18 to 46.