GoYomi 9×9

About the game

GoYomi teaches Go on the small 9×9 board, where a whole game takes minutes and every move matters. You play Black against an AI, and beside the board a coach follows the game: a bar shows who is winning, each of your moves gets a grade, and the coach explains in plain words what it did or missed. This protects the corner; that group is in atari; the AI's last move doesn't need an answer. Point at its suggestion to preview the better move and how play would go on, and click it to play that instead.

There are nine AI levels, from Pebble, which has just learned the rules, to Phoenix, which reads the longest. All of them are a KataGo neural network, the network behind one of the strongest Go programs, running inside your browser; the lower levels play on instinct and choose more loosely, so their mistakes look like a learner's. Win a game and the next one is a level up; lose and it steps down. Handicap stones and komi can be set for each new game, and you can play White, or both sides to study a position.

When both players pass, the coach marks the stones it thinks are dead (click a group if you disagree) and counts the board. After each game, Key moments picks the two or three mistakes most worth a look at your level.

GoYomi was made by Frank Force in 2026 and released as free software.

Playing it here

This is the game as its author publishes it, unchanged. Everything runs in your browser, the AI included, and nothing is sent anywhere. The AI's network is about 2 MB and loads with the game. Your current game and your settings are kept in this browser; clearing the site's data erases them. Games can also be saved and loaded as SGF files, the usual format for Go records. The game is in English.

Controls

Other letter keys switch the board overlays, such as liberties (L), atari alerts (A) and territory (T). Speak announcements in the settings reads every move and comment aloud.

The rules in short

Black and White take turns placing a stone on an empty intersection. Stones of the same colour that touch along the lines form a group, and the empty points next to a group are its liberties. Fill a group's last liberty and it is captured and removed; a group with a single liberty left is in atari. You can't play a stone that would have no liberties unless it captures, and you can't recapture straight back in a way that repeats the board (the ko rule).

The game ends when both players pass in a row. GoYomi counts the Chinese way: your score is your stones plus the empty points only you surround, and White gets komi, a few extra points, for moving second.

Tips

Start in the middle or near the corners. The centre point (E5) and the points C3, G3, C7 and G7 are good first moves on 9×9.

Watch the liberties. With the liberties overlay on, every group shows how many it has left. A group down to one is in atari: save it or let it go on purpose.

Don't chase what you can't catch. Build your own area while you attack; a group with two separate eyes can never be captured.

Don't pass too early. Fill the neutral points between your area and the AI's first, since each one is worth a point. The coach warns you if you pass while there is still something to gain.