Go Strategy Guide: Liberties, Captures, and Five AI Levels
Go has very few rules, yet every stone changes nearby liberties, connections, and influence across the board. The most reliable learning order is not to memorize opening patterns. First understand why stones are captured, then learn how groups live, and only then compare territory and whole-board value.
Open Go and start a 9×9 computer or two-player game
The short answer: what should I check before every move?
Use four questions: Do any of my groups have only one liberty? Can I capture an opposing group now? How many liberties will my new group have? Is there a larger point elsewhere?
The first two prevent immediate tactical losses. The third checks legality and shape. The fourth stops tunnel vision. A beginner who follows this sequence will improve more consistently than one who simply reacts to the opponent’s last stone.
Board, move order, and objective
Stones are played on line intersections, not inside squares. Black moves first, and the players then alternate. A stone normally stays where it was placed until captured. The objective is to control more area than the opponent while keeping your own groups from being surrounded.
YouToStem uses three board sizes across its five bands. Novice and Beginner play on 9×9, Intermediate and Advanced use 13×13, and Master uses the standard 19×19 board. The board grows, but liberties, captures, suicide, and ko continue to work the same way.
What is a liberty?
An empty intersection directly above, below, left, or right of a stone is a liberty. A lone corner stone can have two, an edge stone three, and a center stone four. Diagonal contact does not connect stones and does not create shared liberties.
What is a group?
Orthogonally connected stones of one color form a group. The entire group shares its outside liberties. Count each empty intersection once, even if it touches more than one stone in the group.
What are atari and capture?
A group with one liberty is in atari. When the opponent occupies that final liberty, the whole group is removed immediately. Capturing stones is not the final objective, but attacking weak groups can create territory, initiative, or influence.
Legal moves, suicide, and ko
After a stone is placed, captures of adjacent enemy groups are resolved before the new group’s liberties are checked. A point that appears surrounded can therefore be legal when playing there captures enemy stones and opens new liberties.
Why suicide is illegal here
If a move captures nothing and leaves its own new group with zero liberties, it is suicide and is illegal in this game. The board remains unchanged and the interface reports that the point cannot be played.
Why a ko cannot be recaptured immediately
Some single-stone captures would let both players capture back forever. Ko prevents an infinite cycle. The player who lost the ko must first play elsewhere, ideally creating a threat the opponent must answer, before returning to fight for the ko.
This implementation checks positional repetition: a placement cannot recreate any complete board position already seen in the game. That handles basic ko and also prevents longer repetition cycles in a way that can be judged reliably by the browser.
Eyes, life, and group safety
A surrounded group normally needs two separate internal points that the opponent cannot occupy together. These are two true eyes. A group with only one eye can still be squeezed from outside and eventually captured.
True eyes and false eyes
An apparent eye is not automatically real. Check the diagonal corners as well as the orthogonal neighbors. If the opponent can cut through a diagonal weakness and eventually enter, the space may be a false eye. Corner, side, and center eye shapes require different amounts of diagonal control.
Seki, or mutual life
In seki, opposing groups share liberties and neither side can fill first without being captured. Under area scoring, stones still count toward their owner’s area, while neutral shared points that are not surrounded by one color normally belong to neither player.
What if life and death are unclear?
Keep playing. This browser game scores the board after two consecutive passes and treats stones remaining on the board as alive. If you believe an opposing group is dead, finish surrounding and capturing it instead of passing early.
Area scoring and komi
The game uses area scoring. Black’s score is the number of black stones on the board plus empty intersections surrounded only by Black. White counts the same way and receives 7.5 komi to compensate for moving second. The half point prevents a tie.
Why use area scoring?
Japanese territory scoring includes an agreement phase for dead stones and more detailed procedures for disputed positions. Area scoring is more dependable for automatic counting and beginner practice: if unsettled groups are played out, the visible board can be counted directly.
When should I pass?
Pass when no useful invasion, enclosure, defensive move, or endgame boundary remains. One pass does not finish the game; the opponent may continue. Two consecutive passes signal agreement to score. Do not pass merely because the next move is hard to find—first check atari groups and unfinished borders.
Opening direction: corner, side, then center
Corners are easiest to enclose because two board edges already form boundaries. A side uses one edge. Center territory requires building every boundary yourself. This is why opening play commonly starts in corners, extends along sides, and only later develops central influence.
The main lesson of 9×9
The board is small, so fighting begins quickly. A move near the center or an important corner often affects the whole game. Do not spend many stones securing a tiny patch while the opponent takes the rest of the board. Connection and cutting matter immediately.
The main lesson of 13×13
The 13×13 board introduces a real choice between local fighting and whole-board value. Winning a few points in one corner may be poor if the opponent receives an entire side. Compare how many regions each candidate move influences.
The main lesson of 19×19
On the standard board, opening stones need room to expand. Stones played too close together are inefficient, but stones with no relationship to one another become thin and vulnerable. Strong play balances corner profit, side development, and central influence.
Connection, cutting, and useful tactics
Connection lets groups share liberties and coordinate. Cutting forces the opponent to manage separate weak groups. Much of Go tactics comes from the contest between these two goals.
- Tiger’s mouth: three stones strongly control a point, creating connection or a capture threat.
- Double atari: one move puts two groups in atari, so the opponent usually cannot save both.
- Ladder: a group escapes in a repeating zigzag; always check whether a distant ladder breaker changes the result.
- Net: instead of chasing in contact, surround the escape route from farther away.
- Snapback: sacrifice one stone, let the opponent capture it, then recapture a larger group after its liberties collapse.
Atari is not automatically urgent. Before chasing, verify that the sequence works and that the opponent cannot gain more elsewhere while you spend moves on a small group.
How to train with the five AI levels
Novice: make every move legal and explain its liberties
Use 9×9 to practice counting liberties, connecting, and capturing one stone. After using Hint, explain which group gains liberties or which opposing group loses them. Do not treat the blue marker as a command.
Beginner: recognize atari and weak groups
The board remains 9×9, while the computer pays more attention to captures and connections. At every turn, identify the group with the fewest liberties on each side before planning an attack.
Intermediate: compare local profit with the largest point
Moving to 13×13 introduces tenuki—playing elsewhere instead of answering locally. Separate moves that truly demand a reply from moves you may ignore in order to take a larger corner or side point.
Advanced: calculate the strongest reply
Advanced AI checks your immediate counterplay more consistently. Before choosing a move, calculate the opponent’s strongest atari, cut, or invasion. Compare the safety of all groups after that reply, not just the stones near your candidate.
Master: manage several groups on 19×19
The Master board tests whole-board coordination. When several groups are weak, do not add one defensive move to each. Search for multi-purpose moves that attack while strengthening your own shape, or connect while taking a large point.
Endgame: turn a lead into a result
After large groups settle, the important moves are boundary plays. Take moves that are large for both sides before small moves that benefit only one side. Estimate value by comparing the score after you play first with the score after the opponent plays first.
A sente endgame move keeps the initiative because the opponent must answer. A gote move gives up the initiative after it is completed. Avoid spending a move to capture an irrelevant stone when a larger boundary remains open elsewhere.
Daily challenges, friend links, and review
The daily challenge derives a fixed level and AI seed from the date, so players receive comparable conditions. A friend challenge stores the level and seed in its link. Compare decisions rather than only the final score.
During review, do not inspect every move equally. Find the first weak group, the first ignored threat, and the moment your evaluation of the board changed. At each position, name two candidates and explain why one serves more purposes.
International rule references and this game’s choices
International Go does not use one universal scoring detail in every event. The International Go Federation connects national and regional associations. The Nihon Ki-in teaches intersections, liberties, forbidden moves, ko, and game completion. The AGA rules were designed to be clear and comprehensive for international amateur play.
YouToStem is a learning game, not a professional tournament referee. For consistent browser adjudication it explicitly uses area scoring, 7.5 komi, no suicide, and positional repetition prevention. Knowing those choices makes it easier to understand how Japanese territory scoring or other tournament rules differ later.
Common beginner mistakes
- Counting liberties for individual stones instead of the connected group.
- Chasing an opponent in atari while one of your own groups also has one liberty.
- Playing many close stones to secure a tiny territory and giving away the rest of the board.
- Mistaking diagonal contact for connection and being cut apart.
- Declaring a group alive without verifying two true eyes.
- Passing before unsettled groups and boundaries have been played out.
The fastest route to improvement is to replace “this point feels good” with testable questions: How many liberties does it add? Which group does it attack? What is the opponent’s strongest reply? What do I gain if the opponent ignores it?