How to Play Reversi (Othello) — Complete Strategy Guide

Reversi is a 19th-century English game; its modern form, Othello, was devised in Japan by Goro Hasegawa in the early 1970s and is the version most people play today. It’s an 8×8 board, 64 black-and-white discs, and one rule: place a disc to sandwich the opponent’s discs in a line, and all sandwiched discs flip to your color. Sounds simple. Is actually deep. Here’s how to play and how to win.

Quick version: Black moves first; every move must flip at least one enemy disc; if you can’t flip anything, you pass; when neither player can move, the player with more discs wins. You can follow along on our free Reversi board, which marks every legal move for you.

The basic rules

Board starts with 4 discs in the center: two white, two black, with each color on a diagonal. Black moves first. On your turn, you must place a disc so that at least one straight line of opponent discs is sandwiched between your new disc and an existing disc of your color.

Every disc in those sandwiched lines flips to your color. If you can’t make a legal move, you pass. Game ends when neither player can move. Player with the most discs wins.

Setup and board notation

Columns are lettered a to h from left to right and rows are numbered 1 to 8 from top to bottom, so the top-left corner is a1 and the bottom-right is h8. In the standard Othello start, White sits on d4 and e5 and Black sits on d5 and e4.

From that start, Black has exactly four legal first moves: d3, c4, f5 and e6. They are mirror images of each other, so it doesn’t matter which one you pick. Each flips a single white disc.

How flipping works, step by step

1. Pick an empty square next to at least one enemy disc.
2. Look in all eight directions from that square: up, down, left, right and the four diagonals.
3. Find a closing disc. In any direction where an unbroken line of enemy discs ends in one of your discs, that whole line flips.
4. Flip every qualifying line at once. One move can flip discs in several directions.

Two details catch beginners out. First, the discs you flip do not set off further flips; only lines that run from the disc you just placed count. Second, you can’t pass by choice: if you have a legal move, you must play one.

Reversi vs Othello: what’s the difference?

Today the names are used almost interchangeably, and most online “Reversi” games, including ours, use Othello rules. The main historical difference is the opening: Othello fixes the four starting discs on the center diagonals, while many older Reversi rule sets let players place the first discs in the center squares themselves. The Wikipedia article on Reversi covers the game’s history in more depth.

Strategy 1: Don’t be greedy

The biggest beginner mistake: flipping the most discs each turn. This is almost always wrong.

Why? Because the more discs you have early, the more frontier you create — empty squares adjacent to your discs. Frontier squares are where your opponent plays to flip you. Minimizing your disc count in the opening is actually correct.

Strategy 2: Corners are king

Discs in the four corners can never be flipped — there’s no opposite side to sandwich them from. Every disc you place adjacent to a corner gives your opponent a route to the corner.

Avoid placing on the C-squares (the edge squares directly next to a corner — a2, b1, g1, h2, etc.) and especially the X-squares (the four squares diagonally adjacent to corners — b2, g2, b7, g7). These are tactical traps. Most beginners lose by playing these too early.

Strategy 3: Mobility wins

Mobility = the number of legal moves available to you. In Reversi, the player with more options usually wins. Force your opponent into positions where they have only 1-2 legal moves; your best move is often the one that minimizes THEIR mobility while preserving yours.

This is why greedy disc-flipping loses: a big flip often hands your opponent new options and leaves you with fewer of your own over the next few turns.

Strategy 4: Edge stability

Edge squares are valuable because they’re harder to flip than central squares. A row of your discs along an edge with a corner anchor is essentially permanent.

Don’t break your own edge structure by placing in the center when you have a clean edge. Solid edges + corner anchors = permanent discs = wins.

Strategy 5: Endgame counting

In the last 10-15 moves, exact counting matters. Calculate every move’s exact disc gain and loss for the next 2-3 plies, and look for chances to make your opponent pass. (At the other end of the game, openings are well studied too: the first moves fall into Diagonal, Perpendicular and Parallel structures, and dozens of named lines such as the Tiger branch from them.)

A useful endgame habit is to look at the separate empty regions left on the board. Strong players think in terms of parity: they aim to make the last move in each region, because a final move there can’t be answered.

The three phases of a game

Phase	Roughly when	What to focus on
Opening	First 15–20 moves	Stay in the center, flip few discs, keep your frontier small
Midgame	Until about 15 squares are left	Limit your opponent’s moves, avoid X- and C-squares, fight for edges
Endgame	Last 10–15 moves	Count exactly, grab corners, aim to get the last move in each region

Common beginner mistakes

• Racing to the edges. An early edge disc with no corner support can often be attacked from both sides.
• Playing an X-square to escape a tight spot. It usually hands over the corner a few moves later.
• Judging the game by the disc count. The score in the middle of a game says little; a player far behind on discs can still win easily.
• Forgetting the pass. If your opponent has no legal move, you play again. Setting up a forced pass is one of the strongest things you can do.

Practice

Play our Reversi on Medium and Hard. The computer uses minimax search with corner-heavy positional weights and a mobility term: Medium looks 4 moves ahead, Hard looks 5. You can also play a friend on the same device. Once you beat Hard consistently, you’ve absorbed the corner, edge and mobility ideas above.

Against the computer you play Black, so you always move first. Golden dots mark your legal moves, passes happen automatically, Undo takes back your last move, and the Hint button highlights a suggested move from a 4-move search. Start on Easy, which looks only 2 moves ahead, while the rules sink in.

More

Reversi has a smaller variant: 6×6. Try Reversi 6×6 for faster games where the computer searches deeper (up to 7 moves ahead on Hard). See our how to win at chess for related abstract-strategy depth. If you like placing stones on a grid, Gomoku is another quick board game you can play against the computer; our guide on how to play Gomoku explains the rules, and the best browser board games list has more. When you want a break from thinking, the Chrome Dino game is one key away.

Frequently asked questions

Who goes first in Reversi?

Black moves first under standard Othello rules. In our game, you play Black against the computer, so the first move is always yours.

What happens if you can’t make a move in Reversi?

You pass, and your opponent moves again. If neither player can move, the game ends and the discs are counted.

Can a Reversi game end in a draw?

Yes. If the board fills with 32 discs of each color, or both players are stuck with equal counts, the game is a draw.

Is Reversi the same as Othello?

Almost. Othello is the modern, standardized form of Reversi with a fixed starting position, and most Reversi games today use its rules.

What is the best first move in Reversi?

Any of Black’s four opening moves is fine, since they are mirror images. What matters more is the next few moves: keep your disc count low and stay out of the squares next to the corners.

Related: Mastering Othello (Reversi): Edge and Corner Strategy · How to Play Crazy Eights — Complete Strategy Guide · 10 Games Like Reversi — Free Strategy Board Games Online