Sente is Go on a compact 9x9 board, played against eight AI rivals at a mountain go club. You play Black and move first. Click or tap an empty intersection to place a stone; on a touch screen the first tap shows your stone and a second tap places it, which you can switch off in the pause menu. Stones that share a line form a group, and the empty points touching a group are its liberties. Take away every liberty of an enemy group and it is captured and removed. You may not play a stone that would have no liberties unless it captures, and you may not retake a ko at once.
When neither side wants to play more, pass. Two passes in a row end the game. The club marks dead stones, and Chinese area scoring decides it: living stones plus the empty points only your stones surround, against White's total plus a 6.5 point komi. Beat the rival on your current rung to climb: Hana, Sora, Ume, Tomo, Ren, Kage, Mei, and finally Master Oki. Each rival was measured against the one below it in rival-against-rival matches and won most of them, so every climb is a real step up.
Rival Styles and the Daily Problem
Every rival plays a named style. Ume answers each atari, Sora stakes out corners and sides, Ren presses and cuts, and Kage mirrors your moves across the centre point, so a shape you build is echoed back at you. Lose a game and the club tells you which style beat you, then offers a problem tied to it. A fresh problem also arrives every UTC day, either a short capture drill or a life-and-death problem: capture or kill the marked stones inside the shaded area within the stated number of moves. Solve it daily to keep the streak.
Sente Strategy Tips
On a 9x9 board the centre point and the 3-3 points matter more than the edges. Play the third line to claim territory, and avoid the first line early because stones there have few liberties. Count liberties before every move: a group with one liberty is in atari, and a group with two can often be chased. Keep your groups connected, and watch for stones that two enemy groups could cut apart.
Against territorial Sora, break into the open side before the wall closes. Against aggressive Ren, keep groups with room to make two eyes, since eyes are what keep a group alive. Against Kage, play a move whose mirror image would hurt Kage itself, such as one that threatens a stone near the centre. The word sente means keeping the initiative, so prefer moves that force a reply.
Why Play Go on a 9x9 Board
Go is one of the oldest strategy games still played, with roots in China more than two thousand years ago, and it is known as weiqi in Chinese and baduk in Korean. The full board is 19x19, which can take hours. A 9x9 board keeps every rule and idea, from liberties and captures to eyes, ko and territory, but a game fits in twenty to forty minutes, which makes it the usual way beginners learn and strong players warm up.
The small board also makes tactics matter from the first move. A single mistake near the edge can cost a group, and a lead of a few points decides the result, so the 6.5 komi is large relative to the board. That is why Sente scores by area: every stone you keep alive counts, and every capture you avoid is a point you keep.
Reading Ranks: Kyu and Dan
Real Go ranks count down in kyu from a beginner to one kyu, then up in dan. Sente does not claim those ratings: its eight rivals carry club titles from novice to club master, and their order comes from playing the rivals against each other, where each one beat the rival below it in most games. Hana and Sora pick moves from their style alone, and are easy to beat if you simply count liberties. From Ume upward every rival also reads ahead: a Monte Carlo tree search tries its favourite moves in many quick simulated games before it plays, and the higher the rung, the more lines it reads. Master Oki reads by far the most, so expect to wait a moment while the club master thinks.
The daily problem is a short training drill in the spirit of tsumego, the Japanese name for life-and-death puzzles. The capture drills ask for the move that takes the last breath of a marked group before it escapes, and the life-and-death problems ask for the vital point of its eye space, such as the middle of a straight three or the bend of a bent three. On the board, a short chime, stone clicks and a capture sound play after your first tap, and the speaker button mutes them. They are deliberately small, so you can solve one on a break and keep your streak. Saved progress means you can leave a game half finished and come back with Continue.
Frequently Asked Questions
How does scoring work in Sente?
Sente uses Chinese area scoring on the 9x9 board: you count your living stones plus the empty points only your stones surround, and White gets a 6.5 point komi because Black plays first. The game ends when you and your rival pass in a row. Then the club counts: groups that cannot escape capture are marked dead with a cross and taken off, judged from hundreds of quick simulated endings of the position. Accept the count, or choose Play on and capture a group yourself if you think the marking is wrong.
What is the ko rule here?
Simple ko: if a rival captures a single stone that was itself in a one-liberty position, you may not immediately retake. A small red square marks the forbidden point. Play somewhere else first, and the ko point opens again after the next move pair.
Why is my move refused as illegal?
Two things stop a move. Suicide, where your stone or group would have no liberties and capture nothing, is forbidden. The ko point is also blocked for one turn. Capturing the opponent's last liberty is always allowed even when your own stone looks surrounded.
How do the rival playing styles differ?
Each of the eight rivals is built around a named style. Hana wanders, Sora stakes out corners and sides, Ume answers every atari, Tomo chases captures, Ren attacks and cuts, Kage mirrors your moves across the centre point, Mei weighs territory against attack, and Master Oki reads the deepest. From Ume upward each rival checks its style's favourite moves with a tree search over quick simulated games, reading more the higher it stands, and each rival beat the one below it in measured matches. Beat a rival to climb from novice to club master. The ranks are the club ladder titles, not official Go ratings.
How does the daily life-and-death problem and streak work?
Each UTC day gives one problem from a set of 23, drawn zoomed onto the part of the board it uses. Ten are life-and-death problems, where Black must find the vital point that kills the marked white group, and thirteen are short capture problems; either way Black must capture the marked stones within the stated number of moves. Solve it and your streak grows by one; miss a day and it restarts. After a ladder loss, the Study button picks a problem tied to the style that beat you.
Is my progress saved?
Yes. Your rank, the game in progress, rivals beaten, daily streak and personal best are saved in this browser after every move and when you leave the page. Choose Continue on the title screen to resume. Each rival has its own leaderboard, ranked by how much you won by; only wins are submitted, rematches included, and resigned or lost games never are.
