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Reversi Strategy and Tips

Here is how to think about winning at Reversi, split into short lessons. Each one reads on its own, and each one comes with a real position: press Try it on the board and you play the move yourself.

See the openings

Take the corners

Lesson 1

Corners are the first thing to learn in Reversi. The four corner squares can never be sandwiched, because there is no square beyond them on either side. Whatever happens elsewhere, a disc in a corner stays your colour until the last move of the game.

Corners are not strong because they are worth one disc. They are strong because the discs joined to them stop flipping as well. In this position Black already holds a whole column down the left edge. Taking the corner at the bottom of it turns that entire line into stable discs that White can never win back.

Leave a corner open and your opponent simply takes it on the next move. While a corner is empty, ask two questions before you play: can I take it now, and does this move hand it over?

Avoid the X-squares

Lesson 2

The four squares diagonally next to a corner are called X-squares. Put a disc on one and your opponent can normally sandwich it by playing the corner itself. The move that feels like it is guarding the corner is the move that gives it away.

In this position, playing the X-square beside the top-left corner lets White take that corner on the very next move. You flip one disc and lose a corner for it. The two squares orthogonally next to a corner, the C-squares, are risky for the same reason — less so than X-squares, but still nothing to hurry into.

While a corner is empty, stay away from the squares around it and play towards the middle instead. Once the corner has been filled, its neighbours are no longer dangerous. The rule only applies while the corner is open.

Give your opponent fewer moves

Lesson 3

The disc count in the middle of a game tells you almost nothing. What matters is how many squares your opponent can play. The fewer legal moves they have, the more often they are forced into a move they would rather avoid.

Flipping a lot of discs spreads your colour to the outside of the position, and that outer edge is exactly where your opponent gets to play next. Here the move that flips five discs leaves White eleven replies; the move that flips a single disc leaves seven. Counting the empty squares around the discs you flip is called open-degree, or frontier, counting.

So the guide is: flip few discs, and keep them towards the middle. It is only a guide — a one-disc move does not always cut your opponent's options. Once you are comfortable, count their legal squares before you play.

Count it out in the endgame

Lesson 4

When only a few squares are left, put the general rules aside. The game is decided by the final disc count, so in the endgame you count what each move actually leaves on the board.

Here Black leads 34-28 and two squares are open. The corner is tempting, but it flips a single disc, and White answers in the last square to win 33-31. Playing next to the corner instead flips seven, leaves White with no legal move, and ends the game 42-21. That was the square lesson two told you to avoid — in the endgame, the count comes first.

Three things to look at near the end: how many moves are left, whether your opponent will have to pass, and who plays the final move. Nothing flips the last disc back, so keeping the final move for yourself is worth a lot.

Openings start with three shapes

Lesson 5

An opening line, or joseki, is a sequence that has been played again and again and found not to cost either side much. Reversi and Othello use the same board, discs and rules, so the lines known as Othello openings work unchanged in Reversi.

The shape is settled by the first three moves. Black has four legal first moves, but they are mirror images of one another, so opening lines are normally written as if Black started on f5. White then has three replies: d6, flipping in a vertical line, is the perpendicular opening; f6, flipping diagonally, is the diagonal opening; and f4, alongside Black's disc, is the parallel opening. Perpendicular is the most common and diagonal the next. Parallel is rarely played, because White is considered to be worse off once Black answers correctly.

The third move gives the line its name. From the perpendicular opening, c5 is the Rabbit and c3 the Tiger; from the diagonal opening, e6 is the Ox. Before memorising long lines, learn to tell the three second-move shapes apart — every line grows out of one of them.

Try it on the board

Pick a lesson and the board starts from that position. Start over as often as you like.

Now put it to work

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Last updated 2026-09-13 · Run by Qdan, Inc.