Reversi — also known as Othello — is a game that’s famously “a minute to learn, a lifetime to master.” The rules are simple: place discs to outflank and flip your opponent’s pieces. But winning requires understanding a few key strategic principles.

The Golden Rule: Corners Win Games

Corners are the most valuable squares on the board. Once you place a disc in a corner, it can never be flipped. A corner also anchors the entire edge, making adjacent discs permanently safe.

Priority number one: Get corners. Priority number two: Don’t give your opponent corners.

Key Strategic Concepts

1. Avoid the X-Squares

The squares diagonally adjacent to corners (called X-squares) are the most dangerous squares on the board. Playing on an X-square usually gives your opponent the corner. Avoid them unless you’re certain the corner is already safe.

2. Edges Are Powerful (But Tricky)

Edge discs are hard to flip because they can only be outflanked along the edge or diagonally inward. But carelessly playing on the edge — especially the C-squares (one space away from the corner on an edge) — can give your opponent corner access.

Safe edge play: Fill edges from the corner outward, or only play edges when you can complete a full, stable line.

3. Fewer Discs Can Be Better

This is counterintuitive: in the midgame, having fewer discs is often an advantage. Why? Because having fewer discs means your opponent has fewer places to play — which means they’re more likely to be forced into bad moves (including giving you corners).

The principle: Don’t try to flip as many discs as possible early on. Instead, flip as few as possible while maintaining mobility.

4. Mobility Is Everything

Mobility means the number of legal moves you have. A player with no legal moves must pass. A player with many moves can choose the best one. If you can reduce your opponent’s mobility while maintaining your own, you’ll eventually force them into giving you key squares.

5. Think About the Endgame

In the last 10-15 moves, the strategy shifts from positioning to pure disc count. This is when you want to start flipping as many discs as possible. Corners and edges you secured earlier become the foundation for massive flips.

A Simple Framework

  1. Opening (moves 1-20): Stay central, flip few discs, build mobility.
  2. Midgame (moves 20-45): Target corners and edges, reduce opponent’s mobility.
  3. Endgame (moves 45-60): Maximize disc count, use your stable positions to flip entire rows.

Ready to Play?

Theory only takes you so far. Play Reversi online and practice reading the board — you’ll be surprised how quickly these concepts click.