The board and how a game flows
Go is played on the 361 intersections of a 19×19 grid. Black moves first, then the players alternate placing one stone at a time. Stones never move once placed unless they are captured. The goal is to control more of the board than your opponent; capturing is a means to that end, not the goal itself.
On your turn you may place a stone on any empty intersection or pass. When both players pass in a row, the game ends and the board is scored. You can also resign if you believe the game cannot be won.
Liberties, atari and capturing
A liberty is an empty point directly next to a stone horizontally or vertically. Diagonals do not count. A lone stone in the middle of the board has four liberties, one on the edge has three and one in the corner has only two, which is why stones near the edge are easier to capture.
Stones of the same color connected horizontally or vertically form a single group and share their liberties. Connecting stones therefore makes them stronger, while separate stones can be attacked one by one. Stones that only touch diagonally are not connected, and your opponent can cut between them.
When a group is down to one liberty, it is in atari. A group in atari can be captured on the next move, so you must either add liberties by extending or connecting, or decide to give it up. When the last liberty is filled, the group is removed from the board.
- Single stone in the center: 4 liberties
- Single stone on the edge: 3 liberties
- Single stone in the corner: 2 liberties
- One liberty left = atari; zero liberties = captured
The ko rule and the suicide rule
A suicide move is one that leaves your own stone or group with zero liberties. Under most rule sets, including Playfulo's, suicide is illegal. The exception is when your move captures enemy stones: removing them gives your stone liberties, so it is a normal capture rather than suicide.
Ko is a shape where each side could capture a single stone back and forth forever. To prevent this, you may not immediately recapture a single stone at a ko. You must play somewhere else first, ideally a threat your opponent has to answer, called a ko threat.
If your opponent answers the threat, you can retake the ko on your next turn. If they ignore it and resolve the ko instead, you collect your gain from the threat. Playfulo uses a simple ko rule that forbids moves returning the board to the position just before.
Two eyes, life and death, and false eyes
An eye is an empty point surrounded by your stones. Because suicide is illegal, your opponent cannot play inside your eye while the group still has other liberties. With only one eye, they can fill every outside liberty and finally play in the eye to capture the whole group. With two separate eyes, they can never play in either one first, so the group can never be captured. That is the core of life and death: a group needs two eyes to live.
A false eye looks like an eye, but your opponent can put the surrounding stones in atari and force you to fill it. In the center, an eye is usually false if your opponent holds two of its four diagonal points; on the edge or in the corner, one diagonal point can be enough. Always check the diagonals when counting eyes.
The shape of the eye space matters too. Three empty points in a straight line have a vital point in the middle: if you play there first you live, and if your opponent does, you die. Four points in a straight line generally live, because whichever end your opponent takes, you take the other and make two eyes. Finding these vital points is where life-and-death study begins.
Ladders and nets
A ladder chases a group with repeated ataris in a zigzag until it hits the edge and is captured. The fleeing group can never get more than two liberties. But if one of the escaping side's stones already sits in the ladder's path, called a ladder breaker, the fleeing group connects to it and escapes, leaving the chaser full of weaknesses.
Before starting a ladder, trace the diagonal path all the way to the edge and make sure there is no ladder breaker. Pushing a ladder that does not work can ruin the whole board in one sequence.
A net (geta) does not give atari directly. Instead, you play a loose stone one point away that blocks every escape route in advance. Whichever way the stones try to run, they gain no liberties and are captured. When a ladder fails, check whether a net works instead.
Common beginner mistakes
Even after learning the rules, beginners tend to lose stones the same way over and over. Keeping these points in mind makes games far more stable.
- Missing ataris: every move, check for groups (yours and theirs) with one or two liberties.
- Treating diagonals as connections: diagonally touching stones can be cut.
- Filling your own eyes: a living group can die if you reduce it to one eye yourself.
- Saving dead stones: adding moves to a group that cannot live just loses more.
- Running a ladder without checking for a breaker: every chasing stone becomes a weakness.
- Counting false eyes as real: if the opponent holds the diagonals, the eye can disappear.
A step-by-step plan for your first game
Rather than trying to understand every move from the start, playing a full game in this order is the fastest way to learn.
- Step 1: Take an empty corner first. Corners make territory with the fewest stones.
- Step 2: Extend from the corner along the side to sketch out your area, without crowding stones together.
- Step 3: When your opponent approaches, count liberties and connect or run with weak stones first.
- Step 4: If an enemy group is in atari, compare capturing it with playing a bigger point elsewhere.
- Step 5: Check that each of your groups has room to make two eyes.
- Step 6: When all borders are settled, fill the remaining neutral points and pass when nothing useful is left.
Practicing Go on Playfulo
Playfulo's Go is a casual 19×19 game you can start in your browser with no sign-up. It uses captures, a simple ko rule and a ban on suicide, and you can pass or resign. The practice AI comes in easy, normal and hard: start on easy to get comfortable with atari and capturing, then move up to test life and death and ladders in real games.
You can also send an invite link to play a friend. If you are both beginners, talking through which stones were captured and how many eyes each group had after every game builds the fundamentals quickly.