StonePath: Go Game 9x9

StonePath is a 9x9 Go trainer. Not a book, not a collection of diagrams — every position on every screen is a board you play on.

WHY 9x9 ONLY

The small board is usually treated as a warm-up for 19x19. StonePath is built for 9x9 alone, and on a board this size the engine can look deep: the app ships 23,915 positions rated by KataGo.

NOTHING TO READ — PLAY IT OUT

Shapes, openings, problems and master games are all live boards. Tap an attacking move in a corner shape and the line plays out, with the opponent answering. Play off the book and the move is not refused: the board hands you free play, so you can try your own idea and watch how it ends. Master games step through move by move, and where the book gives a variation, one tap replaces the rest of the game with it.

A 9x9 OPENING BOOK, EVERY POSITION RATED

43 openings in four families, 229 branches, 1,613 positions — every one with a KataGo evaluation: win rate and score.

THE BOOK DOESN'T STOP WHERE THE DIAGRAM STOPS

Two computed layers sit on top of it. 1,745 positions carry the engine's verdict on every reasonable continuation past the last book move, so you can keep playing and see why the best move is best. 20,557 more answer a different question: you just gave away the advantage — here are the three strongest ways to punish it.

TEN OPPONENTS FROM 20K TO 1D

The bots are not just an engine with its search cut short. They use KataGo's network trained on human games: each bot picks moves the way players of a given rank do, and that rank also steers its search. The order of strength was checked on 9x9: neighbouring bots played sixteen games against each other, and the stronger one won 56% to 81% of them.

EVERY MOVE, NAMED

After a game each of your moves gets a verdict on one scale: best, great, good, inaccuracy, mistake, blunder. The thresholds are set in points and tuned for 9x9 — losing four points on 81 intersections is not the same mistake as on 361.

HELP WHILE YOU PLAY

Three layers you can switch on mid-game: the three best moves lettered on the board, who is ahead and by how much, and the territory map.

1,958 PROBLEMS, 1,932 OF THEM CLASSICS

Gokyo Shumyo (1812) and Guanzi Pu (1660) — the collections generations of players learned from. Difficulty is measured for every problem, and the next one is chosen for your level.

ALSO INSIDE

96 life-and-death shapes, named and settled. Techniques and theory written for the 9x9 board. Chinese or Japanese rules, your choice. A full KataGo engine running on the Neural Engine — no server, no account, no internet. On an iPhone 15 Pro it evaluates 531 positions per second, faster than a rented GTX 1080.

WHAT STONEPATH IS NOT

No 19x19 play against the bot, no online play against people. StonePath is not all of Go — it is learning to play, on the board small enough to understand whole.

FREE, AND WHAT THE SUBSCRIPTION ADDS

Free forever: the lessons, the 9x9 theory, the whole opening book, two opponents, and the start of every problem and shape section. The first seven days open everything.

StonePath Pro adds the engine: position evaluations, the three best moves lettered on the board, play past the end of the book, punishment for a bad move, the territory map, game review, adaptive training, all ten opponents and all 1,958 problems. $4.99 per month or $29.99 per year. Payment is charged to your Apple ID; the subscription renews unless cancelled at least 24 hours before the period ends, and is managed in your Apple ID settings.

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