What is Reversi?
Reversi is a two-player strategic placement game on an 8×8 grid (the same dimensions as a chess board). Each player has discs that are black on one side and white on the other.
You take turns placing discs on the board, and every placement flips one or more of your opponent’s discs to your colour by trapping them between two of your own. When the board is full (or no legal moves remain), the player with more of their colour visible wins.
It’s a one-rule game with extraordinary depth: by the late game, every move flips multiple discs and creates cascading positional consequences.
How to win
When the game ends — either the board is full, or neither player has any legal moves — count the discs of each colour. The player with more discs wins. Ties are possible (32-32) but rare in non-trivial play.
Most matches end with the board nearly full and a final count of around 35-29 or 40-24.
Setup
The board starts with four pre-placed discs in the centre, in a 2×2 diagonal pattern:
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . W B . . .
. . . B W . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .Black always plays first.
Movement rules
A placement is legal if and only if it flanks at least one opponent’s disc between the disc you’re placing and another of your own discs already on the board. The flank must be in a straight line — horizontal, vertical, or diagonal. There must be at least one opponent disc in the flanked line, and the disc at the far end of the flank must be yours.
When you place a flanking disc, all opponent discs in the flanked line(s) flip to your colour. A single placement can flank in multiple directions simultaneously — flipping discs along several lines at once.
If you have no legal move (no placement would flank any opponent disc), you must pass. Your opponent then gets another turn. If neither player has a legal move, the game ends.
A worked example
Starting position. Black plays first. Legal moves for Black are: D3, C4, F5, E6 (the four squares adjacent to the centre that would flank a white disc).
Black places at D3. The white disc at D4 is now flanked between Black’s D3 and Black’s D5 (in the starting setup, D5 is Black). D4 flips to Black:
. . . . . . . .
. . . . . . . .
. . . B . . . .
. . . B B . . .
. . . B W . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .Black now has 4 discs visible; White has 1. White must respond — typically with C5 to flip D5 back to White.
The cascading flips quickly create complex board states.
What makes Reversi great
Reversi has a unique property: disc count fluctuates dramatically through the game. A player can have 25 discs on turn 30 and 5 discs on turn 35. The game punishes greedy play — if you flip many discs early, you’ve placed your discs in vulnerable positions and your opponent will flip them back.
Three things define strong play:
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Corners are permanent. A disc placed in a corner can never be flipped (no piece exists “beyond” the corner to flank it). Corners are the most valuable squares.
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Edges are mostly permanent. Discs on the edge can only be flipped from one direction. They’re more stable than centre discs.
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Mobility matters. A position with many available legal moves is strong; a position where you must pass or play badly is losing. Strong players sacrifice immediate disc count to preserve future mobility.
This reverses casual intuition. Beginners maximise flips on every turn. Advanced players often place discs that flip the minimum number, to keep their position flexible.
Reversi’s history
Reversi was developed in England in the late 19th century. Two Englishmen — Lewis Waterman and John W. Mollett — both claimed to be the inventor, and fought a public dispute over credit; the truth is probably that they developed similar games independently. The original game used a board with no central setup — players added pre-placed discs as part of the opening.
The game faded in popularity through the early 20th century but was effectively rediscovered in Japan in the 1970s by Goro Hasegawa, who modified the rules slightly — most notably, fixing the starting position with the four-disc cross — and rebranded the game as Othello. The name was associated with Shakespeare’s tragedy, with the disc colours and the title-character-vs-Iago dynamic suggested as a thematic parallel.
Othello became wildly popular in Japan and spread globally through the 1970s, with a World Othello Championship held annually since 1977.
The game has been heavily studied:
- Computer dominance: by the late 1990s, the program Logistello (Michael Buro) defeated the reigning human world champion. Modern Othello AI plays at a level no human can match.
- Game-theoretic status: Othello on the standard 8×8 board has long been understood to favour a draw under perfect play, with researchers continuing to push toward a complete formal solution. Recent computational work has narrowed the open questions further; full game-theoretic resolution of Othello remains an active area of game-AI research.
The Reversi/Othello distinction:
- “Reversi” is the older, generic name; not trademarked.
- “Othello” is the trademarked name owned by MegaHouse (Japan) / Pressman Toy (US).
Both names refer to the same game with the same rules. Pop Play uses Reversi as the in-app name.
Reversi strategy primer
A few principles that immediately raise your level:
1. Corners are everything
A corner disc is never flipped. Always take a corner if you can. Conversely, never play a square adjacent to an empty corner — that gives your opponent a reason to take the corner with even more flips.
The four squares diagonally adjacent to corners (B2, B7, G2, G7) are the most dangerous in the entire game. Avoid playing them until very late.
2. Edges are valuable but require care
Edge squares are stable but only partially. A common trap: your opponent forces you to play on an edge that gives them the corner.
3. Don’t maximise flips
A common beginner mistake is playing the move that flips the most discs. This is usually wrong. Strong play keeps your disc count low in the early-to-mid game (sometimes called “mobility play”) so your opponent has fewer flanking options.
4. Plan for end-game parity
The number of remaining empty squares at the end determines who has the last move. Often the player who plays the final move wins. Count empty squares and plan accordingly.
5. Don’t pass unless you must
If you have a legal move — even a bad one — make it. Passing gives your opponent two consecutive turns to dominate.
Reversi on Pop Play
Pop Play uses standard Reversi/Othello rules: 8×8 board, four-disc starting cross, flanking flips, end-of-game disc count. Specifically:
- Smart bot opponents at multiple difficulty levels — the hard AI is brutal.
- Online multiplayer with friends or matchmaking.
- Themed worlds — Jade Court, Crystal Cavern, Frozen Tundra, and Celestial Palace skins suit Reversi’s clean abstract aesthetic.
- Move highlight + flip animation so you can see exactly which discs changed colour.
- Score counter updated live so you can track parity through the game.
Frequently asked questions
What’s the difference between Reversi and Othello?
Same rules, different name. Othello is the trademarked Japanese commercial name; Reversi is the older generic name. Pop Play uses Reversi.
How long is a Reversi game?
Most matches finish in 8-15 minutes — exactly the time it takes to fill a 60-square play area (4 starting squares already placed) at one disc per turn per player.
Can the game end before the board is full?
Yes — if neither player has any legal move. This usually happens with a few empty squares remaining. The player with more discs at that point wins.
What’s the best opening move?
For Black (first player), all four legal first moves are essentially equivalent due to board symmetry. From Black’s second move onward, opening choice starts to matter. Strong players typically play one of several memorised opening sequences.
Can two beginners play Reversi?
Yes — the rules fit on a single page and the legal-move filter (you can only place where you flank) makes illegal moves impossible.
Where can I play Reversi on mobile?
Pop Play has it free. Multiple Othello and Reversi apps exist on iOS and Android with various ad densities; Pop Play’s version is free with no ads.
