Reversi rules and how to play: CPU levels and tips to win

Reversi modes

• Random match (ランダムマッチ): find an opponent online
• Room match (ルーム対戦): play a friend using a room ID
• Play against the CPU (CPU対戦): four levels, Novice, Beginner, Intermediate and Advanced
• Two players (ふたりで対戦): take turns on one screen

Basic rules of Reversi

• The game starts with two black and two white discs placed diagonally in the center of the 8×8 board. Black moves first.
• You can place a disc only where it sandwiches your opponent's discs. You can sandwich in any of eight directions (vertical, horizontal and diagonal), and flip in several directions at once.
• All of the opponent's discs that are sandwiched flip to your color.
• If you have no place to play, you pass automatically and your opponent plays again. You cannot pass when you have a place to play.
• The game ends when the board is full or neither player can play. The player with more discs wins; equal counts are a draw.

How to play on Asobi Lounge

• Small dots mark the squares where you can play. Hover the mouse over one to see the discs that would flip, marked with gold rings. Click (tap) to place a disc.
• A red dot marks the last disc played.
• Against the CPU, Undo (待った) takes back a move. Hint (ヒント), up to three times per game, shows the move the strongest CPU would play.
• Normal (標準) / Fast (速い) changes the flipping speed, and Sound (音) turns the sound effects on or off.

How the CPU levels differ

• Novice: plays almost at random. For players who have just learned the rules.
• Beginner: reads 2 moves ahead and likes to play on corners and edges.
• Intermediate: reads 4 moves ahead and also considers the number of places to play and discs that can no longer be flipped (stable discs). With 10 empty squares left, it reads to the end of the game.
• Advanced: reads deeper for about 1 second per move and reads the game perfectly to the end from 14 or more empty squares. It never miscounts in the endgame.

The first move

Counted by this site's rules, Black has four possible first moves. However, if you rotate or flip the board, all four give the same shape, so none of them is better or worse. The shapes start to differ from White's reply, the second move.

Tips

• A disc on one of the four corners can never be flipped. While a corner is empty, avoid carelessly playing on the square diagonally next to it (the X-square) or right beside it (the C-squares).
• In the opening, it often works better to flip few discs: keep your own places to play and reduce your opponent's choices instead of grabbing many discs.
• When you line discs up along an edge, check that your opponent cannot sandwich them and take the corner.
• In the endgame, counting the remaining squares and reading through to the last move decides the game.

Frequently asked questions

Are Reversi and Othello the same?

The rules are almost the same. "Othello" is a registered trademark of MegaHouse Corporation, so this site uses the generic name "Reversi".

What happens when I have to pass?

If you have nowhere to place a disc, you pass automatically and it becomes your opponent's turn. The screen shows when a pass happens.

How do I beat the Advanced CPU?

The Advanced CPU reads the endgame perfectly, so your best route is to gain more places to play in the opening and middle game and keep it from taking corners. Comparing your moves with the Advanced CPU's moves through Hint is also good practice.

Is Reversi free to play?

Yes, it costs nothing. Games against the CPU and solo modes work right away without signing in. Online play (random matches and private rooms) and saving stats or leaderboard scores require signing in with a Google account. To play with a friend, your friend also needs to create an account and register as your friend.

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