Go: play the classic board game online free

Yes. Go on Util.Ninja is completely free to play online, with no sign-up, no download and no in-app purchases. It runs in your browser on computers, tablets and phones, and your statistics and badges are saved on your own device.

Two players, Black and White, take turns placing one stone on an empty crossing of the grid. Stones never move. A stone or a connected group with no empty neighbouring crossing is captured and removed. When both players pass, the game ends and the player who controls more of the board wins.

Yes. Go is the English name of the ancient board game also called Weiqi in China and Baduk in Korea. It is a traditional game that nobody owns. This is an independent version made for this site, with its own board, stones and artwork, and it is not affiliated with any Go association, server or publisher.

A liberty is an empty crossing next to a stone or group. When the last liberty of a group is filled by the opponent, the group is captured. Ko means you may not make a move that brings the board back to a position it had before, so endless capture loops cannot happen. A move that would leave your own group with no liberty is not allowed unless it captures.

The game uses Chinese area scoring: each player gets one point for every stone on the board plus one for every empty crossing that only their stones surround. White gets 7.5 bonus points (komi) because Black moves first, so there are no draws. The side with more points wins.

At the end of the game the computer plays many quick practice games from the final position to estimate which stones could not survive. Those stones are faded and crossed out before counting. The estimate is good but not perfect, so keep playing until the position is clear: capture or defend anything unsettled before you pass.

Easy plays mostly random moves and is a friendly way to learn. Medium, Hard and Expert use a Monte Carlo tree search, which tries thousands of imaginary games before each move. The higher the level, the more time the computer spends thinking, and the stronger it plays. Expert takes several seconds per move.

The 9 x 9 board is the best place to start: a game takes about ten minutes and the ideas are the same as on bigger boards. The 13 x 13 board gives more room for territory and fighting, takes longer, and earns a score bonus on the leaderboard.

Every day everybody starts from the same 9 x 9 position, with two black and two white stones already placed, and plays Black against the Hard computer. Win to put your score on the leaderboard, and come back tomorrow for a new opening.

Yes. Choose "Two players, one screen" in the game menu and take turns on the same phone, tablet or computer. Black moves first.

Yes. The undo button takes back your last move, even through the computer's reply. The light-bulb button marks a good point with a dashed red ring. Both are just for fun, so use them whenever you are stuck.

Yes. Wins against the computer are ranked on a leaderboard with This month and All time panels, and the daily challenge has its own board. A win scores 300 points plus 5 for every whole point of winning margin (up to 60 points of margin), plus a bonus for the level (Easy 0, Medium 100, Hard 250, Expert 450), plus 100 on the 13 x 13 board. You only choose a nickname, with no sign-up, and you can delete your scores at any time.

Yes. Go works on phones and tablets in portrait and landscape. The first tap on a crossing shows a preview stone and the second tap places it. On a computer you can click, or use the keyboard: arrow keys move the cursor, Enter places a stone, P passes, U undoes and H shows a hint.