Reversi is the classic two-player strategy game also known as Othello. Place discs to flip your opponent’s pieces by sandwiching them. Whoever has the most discs at the end wins.
About Reversi
Reversi is a strategy board game played on an 8×8 grid. Each player has discs that are black on one side and white on the other. The game begins with 4 discs in the center (alternating colors). On each turn, you place a disc of your color on an empty cell such that one or more of your opponent’s discs are “sandwiched” between your new disc and another disc of your color. All sandwiched discs flip to your color. If you cannot make a legal move, you must pass. The game ends when neither player can move. Whoever has the most discs of their color wins. Reversi rewards positional thinking — controlling corners and edges is far more valuable than controlling discs in the center.
How to Play Reversi
- Click any highlighted cell to place your disc. Highlighted cells are valid moves; non-highlighted cells are not legal positions.
- When you place a disc, all opponent discs sandwiched in straight lines (horizontal, vertical, or diagonal) flip to your color.
- You must make a flipping move on every turn. If no legal move exists, your turn is skipped automatically.
- Black moves first. Players alternate turns until neither can move.
- When the game ends, the player with more discs of their color wins. Score is shown at the bottom.
Tips and Strategy
- Corners are the most valuable squares. They cannot be flipped because they have no flanking position. Take corners whenever possible.
- Avoid playing X-squares (the diagonal-adjacent cells to corners). They give your opponent easy access to the corner.
- Avoid C-squares (orthogonal-adjacent to corners) for similar reasons unless you can force the corner.
- Limit your mobility early on. Counterintuitively, having FEWER moves available makes you stronger because you force opponent into bad positions.
- Pay attention to “stable” discs — discs that can never be flipped, typically along edges anchored to corners.
- Edges are valuable but tricky. Premature edge moves can give the opponent flank advantages.
- Late game, count discs carefully. The player with more legal moves usually wins, even with fewer discs at one point.
History and Origin
Reversi was invented in 1883 by either Lewis Waterman or John W. Mollett (both claimed credit). The modern variant called “Othello” was patented in 1971 by Goro Hasegawa in Japan, with slightly modified opening rules. The Othello brand is now sold by Mega Brands. Top-level Reversi/Othello has been computer-solved on smaller boards, but the 8×8 game remains computationally hard. Computers have been stronger than humans at Reversi since 1997 when Logistello defeated world champion Takeshi Murakami.
Variations and Game Modes
Variants include 6×6 Reversi (computationally solved — second player wins), 10×10 boards, anti-Reversi (player with fewest discs wins), and Othello tournaments using strict opening rules. Tic-Tac-Toe-Reversi hybrids combine flipping with line-making.
Frequently Asked Questions
How do you play Reversi?
Place a disc of your color on an empty cell so that one or more lines of opponent discs are sandwiched between your disc and another disc of your color. All sandwiched discs flip to your color. Continue until neither player can move; the player with the most discs wins.
What is the difference between Reversi and Othello?
Othello is a trademarked variant of Reversi with one rule difference: Othello starts with a fixed center configuration (alternating colors), while early Reversi let players choose their first 4 discs freely. Modern play almost always uses the Othello rules.
Why are corners so important in Reversi?
Corners cannot be captured because they have no flanking position. Once you take a corner, that disc is yours forever. Corners also anchor stable edges, dramatically increasing your final disc count.
What is an “X-square” in Reversi?
An X-square is the cell diagonally adjacent to a corner (positions like b2, b7, g2, g7). Playing an X-square typically gives the opponent easy access to the corner. Avoid X-squares unless you can force the resulting corner play.
Can the AI in this Reversi be beaten?
Yes. Our AI uses a simple heuristic: prefer corners > edges > maximize flips. It plays solidly but not optimally. Strong human players can beat it consistently with good corner-control strategy.
What happens if neither player can move?
The game ends and the player with the most discs of their color wins. If both players cannot move on consecutive turns (often happens in late game), the game ends immediately.
Can you skip a turn in Reversi?
You can only skip if you have no legal moves available. If any legal move exists, you must play it. The game enforces this automatically.
How long does a Reversi game take?
A typical game lasts 30 moves total (each player plays 30 turns), or about 5-15 minutes depending on player thinking time. Games on smaller boards are correspondingly shorter.