Reversi Variants — Anti-Reversi, Board Sizes, Classic Rules, and More

Why Variants Exist

Standard reversi — played on an 8×8 board with the fixed Othello starting position — is the most widely played version. But over 140+ years of history, players have developed dozens of variants that change the board size, winning conditions, starting position, or other rules.

Some variants are serious competitive alternatives. Others are casual novelties. All of them illuminate different aspects of reversi’s underlying mechanics.

Anti-Reversi (Misère Othello)

How It Works

Anti-Reversi uses the exact same rules as standard reversi with one change: the player with fewer discs at the end wins.

That’s it. Same board, same flipping mechanics, same legal moves. But the reversed objective creates a completely different strategic experience.

Strategy Changes

Everything you know about standard reversi strategy gets turned upside down:

• Disc maximizing becomes correct: In standard reversi, flipping lots of discs is a mistake. In Anti-Reversi, you want to force your opponent to have more discs
• Corners can be traps: Corners create stable disc cascades — which is bad when you want fewer discs. Taking a corner might commit you to too many permanent discs
• Mobility works differently: In standard reversi, having more moves is better. In Anti-Reversi, having fewer moves can be advantageous — you might force your opponent to make large captures
• Endgame parity reverses: The player who makes the last move gains discs from it — potentially bad in Anti-Reversi

Who Plays It

Anti-Reversi is popular among experienced reversi players as a mental exercise. It forces you to think about the game’s mechanics from a completely new angle. It’s also a useful training tool — understanding Anti-Reversi strategy deepens your understanding of why standard strategy works.

Board Size Variants

4×4 Reversi

The smallest playable reversi variant. With only 16 squares and a 2×2 starting position:

• Games last at most 12 moves
• The game is trivially solved — both players have forced optimal strategies
• Useful for teaching absolute beginners the basic mechanics (flipping, passing, scoring)
• No strategic depth at all — purely a learning tool

6×6 Reversi

A popular reduced-size variant that maintains genuine strategic depth:

• Game length: About 32 moves (compared to 60 on 8×8)
• Play time: 5–10 minutes per game
• Solved: In 1993, 6×6 Othello was mathematically solved. The second player (White) wins by 4 discs with perfect play.
• Character: Corner strategy and mobility still matter, but the reduced space means games develop faster and are more tactical

6×6 reversi is good for:

• Quick games when time is limited
• Practice focusing on specific strategic concepts without full-game complexity
• Tournament side events and warm-ups
• AI research and testing (smaller game tree)

The fact that 6×6 is solved (White wins) while standard 8×8 is a draw illustrates how board size affects game balance.

10×10 Reversi

An expanded variant for players who want deeper, longer games:

• Game length: About 96 moves
• Play time: 45–90 minutes per game
• Character: All standard strategies apply but with additional complexity layers. The board has 12 non-corner edge squares per side (rather than 6), creating more complex edge formations
• Not solved: The 10×10 game tree is far too large for current computational methods

10×10 reversi amplifies standard strategy:

• Corner battles involve more long-range maneuvering
• Mobility is even more critical — the larger board means more potential moves and more ways to get squeezed
• Endgame counting is harder — humans struggle with perfect parity calculations on 10×10
• Opening theory is essentially unexplored

Other Sizes

In principle, reversi can be played on any even-sided board. 12×12 and 14×14 have been experimented with, but they’re extremely niche. The 8×8 standard remains dominant because it hits a sweet spot: complex enough to reward deep study, simple enough to be accessible.

Classic Reversi Rules

The Original Game

The original reversi rules from the 1880s differ from modern Othello in one important way: the starting position.

Othello (modern standard): The game begins with four discs already on the board in a fixed diagonal pattern. All games start identically.

Classic reversi: Players take turns placing their first two discs each on the four center squares (d4, d5, e4, e5) in whatever arrangement they choose. Only after all four center squares are filled does normal flipping play begin.

What This Changes

The free-placement opening creates strategic decisions before the first flip:

• Black places first: d4 or e5 (by convention). The choice doesn’t matter due to symmetry
• White responds: White can create either a diagonal or parallel arrangement of the center discs
• Black and White complete the center: The specific arrangement affects the early game

This means classic reversi has more opening variety than Othello — the fixed Othello openings (Diagonal, Perpendicular, Parallel) don’t apply because the starting position isn’t fixed.

Who Plays Classic Rules

Classic reversi rules are rarely used in competition — the World Othello Championship uses Othello rules. But some online platforms offer classic reversi as an option, and purists who appreciate the game’s Victorian origins prefer the original ruleset.

Speed Reversi

Time Controls

Speed reversi uses compressed time controls:

How It Plays

Fast time controls change the game significantly:

• Opening knowledge is critical: With seconds per move, you can’t calculate — you need memorized openings
• Pattern recognition dominates: Experienced players recognize positions instantly; less experienced players struggle
• Endgame errors increase: Precise disc counting requires time that speed formats don’t allow
• Reversals happen more: Time pressure causes even strong players to make tactical errors

Where It’s Played

Speed reversi is popular in online play where players want quick games. Most online platforms track speed ratings separately from classical ratings.

Randomized Starting Positions

The Concept

Instead of the fixed starting position, games begin with a randomly generated configuration of the four center discs. This eliminates opening book preparation — neither player has studied the position before.

Variations

• Random color assignment: The four center discs are placed randomly (2 black, 2 white), creating various starting configurations
• Random position: Discs are placed on random squares near the center, not just the four center squares
• Chess960 style: Borrowing from chess’s Fischer Random concept, a set of pre-approved starting positions is published, and one is chosen randomly before each game

Purpose

Randomized openings exist for the same reason Chess960 exists in chess: to test players’ ability to think independently rather than rely on memorized preparation. In a format where opening books are useless, the player with deeper positional understanding has the advantage.

This variant is mostly used in casual and online play. The World Championship uses the standard fixed opening.

Other Variants

Simultaneous Reversi

Both players choose their moves at the same time, revealing simultaneously. If both choose the same square, neither moves. This creates a game-theory element (predicting the opponent’s move) absent from standard reversi.

Team Reversi

Two players per side take alternating turns for their team. Teammates can discuss strategy but one player makes each move. This variant is used in social settings and some team tournaments.

Reversi on Non-Standard Boards

Experimental variants include:

• Hexagonal reversi: Played on a hexagonal grid with six directions of capture instead of eight
• Toroidal reversi: The board wraps around — the top edge connects to the bottom, left connects to right. This eliminates corners entirely, which fundamentally changes strategy
• 3D reversi: Played on stacked boards, with captures possible in three dimensions. Extremely complex and mostly theoretical

Progressive Reversi

Each turn, the number of moves a player can make increases: 1 move on turn 1, 2 moves on turn 2, 3 on turn 3, etc. This creates explosive midgame positions and a very different tempo.

Choosing a Variant

Most players should master the standard 8×8 game before exploring variants. The strategic principles — mobility, corners, stability — transfer across most variants, making standard play the best foundation.