Othello · Beginner guide
Othello Rules: How to Play, Strategy and FAQs
To play Othello, place a disc so that it brackets one or more opposing discs in a straight line, then flip the bracketed discs to your color. Black moves first. If you cannot make a legal move, you must pass; when neither player can move, the side with more discs wins. That short rule explains most of the game, but specific positions can still be confusing. This guide works through an opening and answers the questions that usually arise at the board.
Othello rules: the board and starting position
Use an 8 by 8 board with 64 squares and discs that can show either black or white. Columns are labeled A through H and rows 1 through 8. In the orientation used on this site, the starting discs are White at D4 and E5 and Black at E4 and D5. Each color occupies a diagonal pair in the center. All other squares begin empty.
Black takes the first turn. Each placement must go on an empty square and capture at least one opposing disc. Once placed, a disc stays on its square for the rest of the game; its color can change repeatedly. Do not remove captured discs as you would in some other board games. Flip them in place instead.
A worked example: D3, then C3
At the standard opening Black can choose C4, D3, E6 or F5. Suppose Black plays D3. Follow the column downward: D4 is white and D5 is already black. The new D3 disc and the existing D5 disc bracket D4, so D4 flips. There are now four black discs and one white disc.
White can reply at C3. The diagonal from C3 passes through the black disc at D4 and ends at the white disc at E5. D4 therefore flips back to white, leaving three black and three white discs. Only two new discs have been added, even though a central disc has changed color twice. The diagrams below show these exact positions. In the live game the AI chooses its own response, so C3 is an example rather than a forced reply.
How legal moves and flipping actually work
From your proposed placement, examine eight directions: left, right, up, down and the four diagonals. A capturing line begins with one or more uninterrupted opposing discs and ends at a disc of your own color. A blank square breaks the line. Meeting your own disc immediately does not capture anything, and you cannot jump over a friendly disc to reach opponents farther away.
Check every direction from the new disc. If three separate lines qualify, all three lines flip. Captures are mandatory, so you cannot select only the line that benefits your plan. However, a disc that has just flipped does not trigger another round of captures elsewhere. All captured lines must begin at this turn's newly placed disc.
Legal move hints are a convenience, not an extra rule. On a physical board you must find these lines yourself. When a position seems surprising, trace the line square by square before assuming the software has allowed an illegal move.
Beginner Othello strategy: what to check before moving
First, check whether your intended move gives away a corner. A1, H1, A8 and H8 are corner squares. A disc placed there cannot later be bracketed, making corners dependable anchors. The diagonal neighbors B2, G2, B7 and G7 are often called X-squares. Playing one while the adjacent corner is empty can open access to that corner. It is a warning sign to investigate, not proof that the move always loses.
Second, compare mobility: the legal choices available to each player. Flipping many discs can leave more of your color exposed next to empty squares, allowing the opponent to attack from several places. These exposed pieces are called frontier discs. A quieter move sometimes leaves a more flexible position. Neither 'always flip the most' nor 'always flip the least' is a reliable strategy by itself.
Third, adjust your thinking as the board fills. In a short endgame, calculate the actual remaining placements and possible passes rather than relying only on square preferences. Parity concerns who makes the final move in a region of empty squares. It is useful to study, but a simple count of empty squares is not a complete solution when players can enter different regions or must pass.
A practical review needs only one question: which reply did I overlook? Identify a moment when the opponent gained a corner, restricted your options or changed the final count. Replaying that decision with a different move teaches more than treating every loss as evidence that the opening was wrong.
Practice the rules against the computer
The game on this site assigns you Black. Easy selects random legal moves, Medium uses positional priorities, and Hard searches ahead within a time limit. Start with Easy if you are still tracing capture lines. Move up when you can explain why a move is legal before using the hint dots.
Use Undo to compare a decision while the game is still active. Statistics stay in this browser, and an unfinished board is not restored after a refresh. This is a local AI practice game rather than a multiplayer service, so there are no rooms, public ratings or opponent invitations. These details matter when choosing where and how to practice.
Othello frequently asked questions
1. Are Othello and Reversi the same game?
Modern websites often use both names for the familiar 8 by 8 disc-flipping game. Historical versions of Reversi have used different starting or passing conventions, so check a particular game's rules. This site uses the standard central four-disc setup, Black moving first and mandatory passes only when no legal move exists.
2. Why can I not place a disc on an empty square?
An empty square is legal only if your new disc would bracket an uninterrupted line of opponents against an existing disc of your color. Adjacency alone is not enough. A gap, a friendly disc encountered first, or a line that runs off the board without reaching your color makes that direction invalid.
3. Can I flip diagonally or in several directions at once?
Yes. Captures can run horizontally, vertically and diagonally. Check all eight directions from the newly placed disc. Every qualifying line flips, so one placement can change several rows of opposing discs. Each line must still be straight and complete; a bent path around the board does not count.
4. Do flipped discs create a chain reaction?
No. Only lines directly bracketed by the disc placed this turn are captured. Newly flipped discs do not act as additional placements. If a different line appears surrounded after the first flips, leave it alone unless it was also a direct capturing line from the original placement.
5. Can I choose not to flip some captured discs?
No. You must flip every opposing disc directly bracketed by your move, even when a capture seems to help the opponent's next turn. You also cannot make a placement that captures nothing. Choosing the square is the strategic decision; the resulting flips follow the rules automatically.
6. What happens when I have no legal move?
You must pass, and the other side gets another placement if it can move. This site handles that automatically. If your opponent's move gives you a legal option again, you resume taking turns. A pass does not remove your existing discs or immediately declare that you have lost.
7. Can I pass even when a legal move is available?
No. You must play when at least one legal square exists, even if every option looks unappealing. Being forced to choose between poor moves is part of Othello strategy. You cannot wait for the opponent to improve the position before deciding where to play.
8. Why did the computer move twice in a row?
After its first placement, you may have had no legal move while the computer still had one. Your turn was therefore passed, and it played again. The same situation can favor you if White cannot move. Check the turn message and available hints before treating a consecutive move as a bug.
9. Can the game finish before the board is full?
Yes. The game ends when neither side has a legal placement, even if empty squares remain. One player's inability to move is not enough while the other can continue. A full board also ends play because it leaves no vacant square for either color to use.
10. How do you score Othello, and what happens in a tie?
This site counts the black and white discs visible at the end. More discs wins; equal counts produce a draw. It does not automatically award empty squares to the winner. Tournament organizers may use additional score conventions, including special treatment of empty squares or a complete wipeout, so check those rules when recording a competition result.
11. Does taking a corner guarantee a win?
No. A corner disc is stable because it cannot be bracketed, but the rest of the board still matters. Your opponent may retain stronger mobility or finish with more discs elsewhere. Corners are valuable strategic opportunities, not a substitute for checking legal responses and the final score.
12. Should I flip as many discs as possible early on?
Not automatically. Only the final count decides the result. An early capture can expose more of your discs and give the opponent useful choices. Compare corner access and the replies each move allows. A smaller capture can be better, but deliberately having fewer discs is not a winning condition either.
13. How strong are the three computer levels?
Easy is random legal play, Medium favors selected positional features, and Hard uses Alpha-Beta search with iterative deepening. Hard aims for up to six plies within about 1.5 seconds of search time. Device speed and the position affect the completed search. These levels have no verified Elo ratings and do not promise perfect play.
14. Do I need an account, payment or a cloud AI service?
The current game needs none of those. Open the page and play against an AI that calculates locally in the browser. Initial loading still requires the website's resources, and there is no guaranteed offline reload. You cannot invite another person into this board; its opponent is the computer.
15. What does Undo do, and does refreshing save my position?
Undo returns to an earlier turn where you can choose a move, usually before your last placement and the computer's answer. Passes can make that sequence longer. Refreshing starts a new board rather than recovering the unfinished position. Completed statistics are separate and remain in this browser unless its stored site data is removed.
16. Is there an opening that makes me win every game?
No opening sequence guarantees a win against every response. An opponent can choose different replies, and a memorized line soon stops applying. Learn what your opening move changes: capture lines, available replies and access to corners. Then practice responding to the position actually on the board rather than forcing a preset script.