What is eye space in Go?

Eye space is the empty area enclosed by a group, the room it has to make eyes. Its shape matters as much as its size: a straight four lives, a square four dies, and shapes like the straight three, bent three and rabbity six are decided by whoever plays first.

How do you find the vital point in Go?

The vital point is usually the empty point that touches the most other empty points in the eye space. It is the middle of a straight three, the bend of a bent three, the center of a crossed five or rabbity six, and the square point next to the tail in a bulky five.

How is seki scored in Go?

Under Japanese territory scoring, no points inside a seki count for either side. Under Chinese area scoring, the stones count but shared liberties do not. Playfulo's automatic count is casual, so seki and dead stones may be handled differently from tournament rules.

Why is a square four dead in Go?

Wherever the defender plays inside a 2×2 square, the remaining three points form a bent three, and the attacker takes its vital point at the bend. Two eyes can never form, so the square four is dead no matter who moves first.

Go Life and Death: Eye Shapes, Vital Points and Seki

What eye space is and why shape matters

Eye space is the empty area a group encloses: the room it has to form eyes. Two eyes are always the goal, but three empty points in a straight line behave very differently from three points bent into an L, and four points in a row are nothing like four points packed into a square. Half of life-and-death skill is simply recognizing these shapes and knowing the result without reading out every move.

The results below assume a few things: the surrounding wall has no cutting points, nothing has been played inside the space yet, and the group has enough outside liberties. In real games a cutting point or a shortage of liberties can flip the verdict, so treat the shape results as a starting point and always check the wall as well.

Sort every shape into one of three outcomes: alive no matter who moves, dead no matter who moves, or unsettled, meaning whoever plays first decides. In unsettled shapes a single point, the vital point, decides everything, and finding it is usually the answer to the problem.

Three- and four-point eye spaces

Start with three points. In a straight three, the middle point is vital. If the defender takes it, the two ends become separate eyes and the group lives. If the attacker plays there first, the defender can capture that stone but is left with only a single one-point eye. A bent three works the same way, with the corner of the bend as the vital point.

Four-point spaces split three ways. A straight four and a bent four (an L shape) are alive: the two middle points are miai, so if the attacker takes one, the defender takes the other and gets two eyes. The T-shaped four, sometimes called the pyramid four, has its vital point on the point touching the other three, so it is unsettled. The square four, a 2×2 block, is dead: wherever the defender plays, the remaining three points form a bent three and the attacker takes its vital point.

The corner has special cases whose ruling can depend on the rule set, because the edges cut off liberties in two directions. Learn the center and side results first, and read one step further whenever a shape touches the corner.

Straight three: unsettled, vital point in the middle
Bent three: unsettled, vital point at the bend
Straight four: alive, the two middle points are miai
Bent four (L shape): alive, the two middle points are miai
T-shaped four: unsettled, vital point where the three arms meet
Square four: dead, no two eyes whoever moves first

Five and six points: bulky five, crossed five, rabbity six

From five points on, the general pattern is that compact shapes are dangerous. The bulky five, a 2×2 square with one extra point attached like a tail, has its vital point at the square point that touches the tail. The crossed five, shaped like a plus sign, has its vital point in the center. Both are unsettled: the defender lives by taking the vital point, and the attacker kills by placing there first.

The best-known dangerous six is the rabbity six, also called the flower six: a crossed five plus one extra point tucked diagonally between two of its arms. Its vital point is the center, which touches four of the other points. A rectangular six, three points by two, is normally alive in the center or on the side because every placement has an answer, although it can run into trouble in the corner once outside liberties are filled.

A useful rule of thumb: long, stretched spaces lean toward life, while spaces clumped around one point tend to have that point as their vital point. Even without memorizing names, the empty point that touches the most other empty points is usually the place to look first.

Bulky five: unsettled, vital point is the square point next to the tail
Crossed five (plus shape): unsettled, vital point in the center
Rabbity six: unsettled, vital point in the center
Rectangular six (3×2): usually alive in the center or on the side

Vital points, placement and reducing from the outside

A placement, often called nakade, is a stone played on the vital point inside the opponent's eye space. It does not need to live. Even if it is captured later, it has done its job if it stopped two eyes from forming. The attacker can add more stones inside so that, once captured, they leave behind a dead shape such as a straight three, square four or bulky five, and then play the vital point again.

When the space is too big for a direct placement, reduce it from the outside first. The main tool is the hane at the end of the space. On the edge, a first-line hane shaves off a point at a time, turning a straight four into a straight three or a wide space into an unsettled one. Hane from both sides, then place on the vital point: that is the most common killing sequence.

A throw-in is another tool. You sacrifice a stone next to a potential eye so that after the capture the point turns into a false eye that eventually has to be filled. Defenders should think in reverse: widen the space before the opponent can hane, and if the shape is unsettled, take the vital point first.

Seki: living together without two eyes

Seki is a standoff in which a black group and a white group share liberties and neither can fill them without putting itself in atari. Picture two groups with no eyes that share exactly two liberties. Whoever fills one of them leaves their own group with a single liberty and gets captured, so nobody touches them and both groups stay on the board. Two groups that each have one eye and share one liberty are in seki for the same reason.

Seki usually comes out of a capturing race where the liberty counts balance out. Turning a group that looked lost into a seki is a real skill, and the opposite mistake, filling a shared liberty and letting a winning race end in seki or worse, is common. Once a seki exists, never be the first to fill a shared liberty.

Rule sets score seki differently. Japanese territory scoring counts no points inside a seki, while Chinese area scoring counts the stones but not the shared liberties. Playfulo's Go uses simple Chinese area scoring, but the count is a casual automatic one, and the game notes that life-and-death and seki situations may be handled differently from tournament rules. It is safer to actually capture stones you believe are dead before passing, and to leave seki points alone and check the final count.

A step-by-step routine for life-and-death problems

Guessing works for a while, then stops working. Thinking through problems in the same order every time is what builds real strength, so follow these steps even on easy problems.

Step 1: Decide whose move it is and what the goal is: live, kill, or settle for seki or ko.
Step 2: Count the eye space and name its shape. Is it close to a straight three, square four or rabbity six?
Step 3: Look for weaknesses in the wall: cutting points, diagonal points that could create false eyes, and outside liberties.
Step 4: List candidate moves in three groups: the vital point inside, hanes that shrink or widen the space, and throw-ins.
Step 5: Read against your opponent's best reply, not the reply you hope for.
Step 6: Check the final position: two real eyes, no dead shape left for a second placement, and no surprise ko or seki.
Step 7: Review wrong attempts and write down in one line why they failed, so you spot the shape instantly next time.

Common life-and-death mistakes

Most life-and-death errors come from misjudging a shape or reading one move too few. These are the ones that show up most often as players move from beginner to intermediate.

Starting inside: placing too early in a wide space lets the defender answer broadly and live. Reduce from outside first.
Only answering hanes: the defender should widen the space or take the vital point before the hane comes.
Thinking a square four lives: it looks roomy, but it is dead whoever moves first.
Forgetting shortage of liberties: filling your own outside liberties can suddenly make a placement or throw-in work.
Filling a shared liberty in seki: the moment you do, your own group is in atari.
Judging the corner like the side: fewer liberties and edge effects can change the result of the same shape.
Not reading the shape after a capture: taking three or four stones is useless if the space left behind is dead.

Practicing life and death on Playfulo

Shapes learned from problems stick best when you see them in real games. Playfulo's Go runs on a 19×19 board in your browser with no sign-up, and you can choose an easy, normal or hard practice AI. When enemy stones get squeezed into a corner or along the side, count the eye space, place on the vital point and see whether the kill really works. When your own group is cramped, practice taking the vital point first.

You can also invite a friend by link and go over the dead stones and seki positions together after the game. Because the automatic count may differ from tournament rules, getting into the habit of capturing dead stones before the game ends also makes the result more accurate.