Choose a mode in the sidebar: Human vs Human (two players share the mouse), Human vs AI (pick your color and the AI level), or AI vs AI (pick a level for each color and watch). Choose a board size — 9×9 is recommended for learning — set komi if desired, and press New Game. Black always moves first.
Everything is mouse-driven. Hover over the board to preview a stone, and click an empty intersection to play it. Sidebar buttons: Pass skips your turn, Undo takes back the last move (in Human vs AI it takes back the AI reply too), Resign concedes the game. In AI vs AI mode, Pause halts play.
Black plays first, then players alternate. You may pass instead of playing. There is no limit on game length except the board filling up.
Stones are placed on the intersections of the grid lines, not the squares. Once placed, stones never move — they can only be captured. You may play on any empty intersection except: a point where your stone would have no liberties (suicide), or a play that would repeat a previous board position (the ko rule).
A group of connected stones is captured and removed when its last liberty (adjacent empty point) is filled by the opponent. Captures are shown in the sidebar counters. The game uses area (Chinese) scoring: your score is the number of your stones on the board plus the empty points only your stones surround. White adds komi (default 6.5) as compensation for moving second.
When both players pass consecutively, scoring begins: click any group to mark it dead (it becomes translucent and counts as the opponent's territory), then press Accept Score. The higher score wins. You also win immediately if your opponent resigns.
After two consecutive passes, the Scoring Assistant appears with a live breakdown for the selected Chinese area or Japanese territory rules. It shows both totals, the contributing stones, territory, prisoners and komi, the number of neutral points, and how many Black and White stones are currently marked dead.
Choose Next Disputed Group to cycle through unmarked groups with one or two liberties. An amber dashed ring identifies the complete group. Decide its status yourself, then select the group on the board to mark or unmark it as dead. The breakdown and dispute list update immediately. Low liberty is a review prompt, not an automatic declaration that the group is dead.
In Human vs Human games, Black and White must each choose their agreement button before Accept Score becomes available. The confirmations apply to the exact dead-stone markings currently shown. Marking or unmarking any group clears both confirmations, and both players must review the revised score again. Games involving AI make dual confirmation optional.
Use Undo Dead Mark and Redo Dead Mark to reverse or restore group-status changes without resuming play. The status line shows how many scoring changes are applied and whether a redo remains available. Undo and redo both recalculate the score and clear any Black or White confirmations, because agreement with a different position would be impressively useless.
Open Decision Log to inspect every currently applied group-status choice. Entries identify the group color, board coordinate, stone count, alive or dead status, and the resulting Black and White totals. Undo removes its corresponding entry, Redo restores it, and Study Reports preserve the final applied list.
The Initial Margin records the position when scoring begins. Current Margin reflects all applied dead-group decisions. The impact message reports how many points the margin shifted, which player benefited, and whether the leader changed. Marking, undoing, or redoing a decision updates the comparison immediately, and Study Reports preserve the final comparison.
You lose if your final score is lower than your opponent's, or if you resign.
Use one of the three save slots in Games & Files, or rely on the automatic recovery snapshot. Saved games appear in the Game Library and can be restored later. Press New Game to restart. If scoring was entered by mistake, press Resume Play to continue.
The Position Coach explains the current phase, approximate score direction, tactical danger, and the most useful next priority. Choose Brief or Detailed explanations. Coach Move uses the built-in AI to mark a suggested intersection with a cyan ring; it does not play the stone for you. Turn off Live Coaching when you want to study without hints.
Choose Find Candidate Moves to compare three legal possibilities. Candidates are ranked using captures, liberties, connections, pressure, and opening development. Select a candidate card to emphasize it on the board. These are lightweight teaching suggestions, not professional-strength Go analysis.
Export Study Report downloads a self-contained HTML report containing the displayed board, settings, players, captures, result, Position Coach summary, study-mark count, and complete move table. Comments, bookmarks, and Review Lab critical moves are identified. Open the downloaded report in any browser and use its Print button to print it or save a PDF.
Choose Review Game to rate each move as Best, Good, Inaccuracy, or Mistake. The local review compares the played move with other legal choices using captures, liberties, group rescues, connections, pressure, and self-atari. Separate Black and White summaries show the rating totals.
Jump to Weakest Move opens the position with the largest missed local opportunity. The explanation appears below the score graph, compact ratings appear in Move History, and the same details are included in an exported Study Report. The ratings are lightweight study guidance, not professional-engine analysis.
While viewing a reviewed move, choose Show Alternative. The game returns to the position immediately before that move and places a cyan ALT diamond on a useful comparison move. For an Inaccuracy or Mistake, this is the stronger move found by the review; for a Best move, it is the next comparison choice. The analysis text identifies its coordinate.
Choose Practice Alternative to turn that position into a playable branch. The original line is preserved in the variation list, and the suggested point remains highlighted while you decide whether to play it or explore another legal move.
Choose Focus Board or tab to the board. Use the arrow keys to move the cyan intersection cursor, Home to return to the center, and Enter or Space to activate the selected point. Activation plays a stone during normal play, adds or removes the chosen Study Board mark during annotation, and toggles a stone group as dead during scoring. Press Escape to hide the intersection cursor.
When Opening Explorer candidates are current, press 1, 2, or 3 to move the cursor to that candidate. Screen readers announce the coordinate, stone and group details, liberties, study marks, whose turn it is, and whether the board is in replay or scoring mode.
Choose Circle, Triangle, Square, X Mark, or Numbered Sequence in the Study Board panel, then select intersections to annotate the position. Choose Play stones normally to resume play. Marks are included in saved games and in Export Board PNG. Selecting an already marked intersection removes its mark.
SGF import is limited to 4 MB. This prevents unusually large or combined game collections from consuming excessive browser memory. Download and separate a large collection, then import one game at a time.
Start on 9×9 against the Easy AI. Corners are the easiest territory to hold, then sides, then the center. Don't try to capture everything — surrounding territory wins games. A group with two separate eyes can never be captured.