How to play reversi
Reversi is played on an 8Γ8 board that starts with four discs in the center: two black and two white, placed diagonally. Black moves first. On your turn you place a disc so that it outflanks at least one straight line (horizontal, vertical or diagonal) of your opponent's discs β that is, the line is bordered by your new disc on one end and another of your discs on the other end. All outflanked discs flip to your color.
If you have no legal move, your turn is passed automatically. The game ends when neither player can move, usually when the board is full. The player with more discs wins. Small dots show the legal moves (turn off Show moves for a harder challenge). Undo takes back your move and the computer's reply.
Computer levels
Easy looks one move ahead and sometimes plays randomly. Medium searches three moves ahead using a positional score. Hard searches five moves ahead, considers mobility and corners, and plays the last ten moves perfectly by calculating to the end of the game. Results are saved per level on your device only.
Strategy tips
- Corners are gold. A disc in a corner can never be flipped, and it anchors the edges next to it.
- Avoid the X-squares. The squares diagonally next to an empty corner often hand that corner to your opponent.
- Fewer discs early can be better. Grabbing many discs in the opening usually gives your opponent more moves. Aim to have more choices than them (mobility).
- Think about parity. Near the end, try to be the one who plays the last move in each empty region.
- Edges are strong only when stable. An edge disc that can be outflanked along the edge may become a liability.
About reversi
Reversi was popular in England in the late 1800s. A version with a fixed starting position became hugely popular in Japan in the 1970s and spread worldwide; today it is one of the most played abstract strategy games. In 2023 a research team announced that the standard 8Γ8 game is a draw with perfect play. Every game here is free, with no sign-up, and works offline after the first visit.
FAQ
Is reversi the same as Othello?
They are nearly the same game. Othello is a trademarked name for a version with a fixed starting setup, which is the setup used here.
What happens if I can't move?
Your turn is passed automatically and your opponent moves again. If neither side can move, the game ends.
Who moves first?
Black moves first. Use Who starts to let the computer play Black.
Why are corners so important?
A corner disc can never be flipped, and it lets you build stable discs along both edges.
Can I play reversi offline?
Yes. After the first visit the page is cached and works without internet on phone and computer.