The corner is the best place in Go to make a small living group — and also the place where groups die most unexpectedly. Both facts come from the same geometry: the two board edges enclose space for you, but they also take away liberties and room to manoeuvre. This article covers the basic ideas you need for life and death in the corner.
Why the corner helps you live
To make two eyes, a group needs an enclosed space. In the corner, the two edges already form two walls of that space. A handful of stones can enclose a space big enough for two eyes. That is why an invasion at the 3-3 point under a star point can often live, and why corner territory is so efficient.
Why the corner is dangerous
The edges that help you also hurt you:
- Fewer liberties. Stones on the edge and in the corner have fewer liberties, so they run out of breath quickly in a fight.
- Shapes behave differently. Some eye shapes that live on the side are weaker in the corner, because the corner point itself creates special weaknesses.
- Less room to escape. A corner group that cannot make eyes can only escape toward the centre, often through a narrow gap.
Key ideas for corner groups
The 1-2 point and the corner point
The points right next to the corner — the 1-2 points — are often vital in corner fights. A stone there can take away eye space or make an eye false. When a corner group is short of space, look first at these points.
Reducing from the edge
The attacker often slides along the first or second line to shrink the corner's eye space. Each slide removes a potential eye point. Defending means blocking these slides at the right moment.
The vital point inside
Once the space is small, there is usually one point inside that decides whether it can be split into two eyes — the vital point. See eye shapes and vital points. In the corner, the vital point is often on the second line.
Common situations
- The 3-3 invasion under a star point. With correct play early in the game, the invader normally lives. Later, if the outside is strong and the invader's space is reduced, it may die.
- A 3-4 corner without an enclosure. Invasions and approaches are both possible; an enclosure removes most of the danger.
- A group crawled into the corner. A group pushed along the second line into the corner often has just enough space for one eye — not two.
Habits that keep corner groups alive
- Claim enough space early. A corner group with room along both edges lives easily.
- Block slides in time. When the opponent slides along the edge toward your corner, block before your space shrinks too much.
- Take the vital point when unsettled. If your group's life depends on one point, play it.
- Count real eyes. Use the diagonal test to check for false eyes; see false eyes.
- Keep a way out. If the corner space is small, keep a connection toward the centre or to your other stones.
Habits for attacking corner groups
- Reduce first, then play inside. Take away space from the edge, then aim at the vital point.
- Look at the 1-2 points. They often decide the fight.
- Do not rush. If the group cannot live anyway, there is no need to spend moves on it now; if it can, attacking it too early may only help it settle.
Practise
Try invading corners in games against the computer on the home page, and let the computer invade yours. Notice when the invader lives and when it dies, and what the last few moves were. When playing people on the online page, sign in on your account and replay corner fights after the game.
Related: two eyes to live, how to study life and death, the star-point approach and the 3-3 invasion.
Why corner reading pays off
Corner life and death is worth special effort because corners hold so much of the territory in a typical game. A corner group that dies usually costs not only its own stones but the whole corner area, which the opponent then owns. Conversely, a successful invasion into your opponent's corner can swing the game completely. Many close games are decided by a single corner fight in the middle game, often around the 3-3 point or along the second line. Players who have studied the basic corner shapes see these swings coming and act a move earlier.
A practical way to build this skill is to watch for every corner group in your own games that ended up with a small eye space, and replay how that space was reduced. Over time you will recognise the moment when a corner becomes unsettled — usually right after the opponent's first slide along the edge.
Living small versus dying big
A corner group that is short of space faces a choice: live small in the corner, or try to claim more and risk dying. Beginners almost always reach for more. But a small living group in your opponent's corner is often a big success — it removes territory your opponent was counting on. When you invade, aim first to live, then to gain; when you defend against an invasion, aim to make it live as small as possible rather than to kill it at any cost.
The corner at the end of the game
Corner life and death matters right up to the last moves. Before you pass, look at every corner group once more, yours and your opponent's. Is there a slide along the edge that would shrink an eye space? Is there a 1-2 point that would make an eye false? Because the final count on this site is literal, a corner group that can still be killed will be killed by a careful opponent, and the whole corner will change hands. A final check of the corners takes seconds and protects the largest territories on the board.
Frequently asked questions
Why can a 3-3 invasion usually live?
Because the corner edges help enclose enough space for two eyes, especially early in the game.
Are all eye shapes the same in the corner?
No. The corner can weaken certain shapes, so read carefully.
What are the 1-2 points?
The points on the edge right next to the corner point. They are often key in corner fights.
Should I always try to kill a corner invasion?
Only if it can really be killed. Otherwise, make it live small and take the outside.
How do I get better at corner life and death?
Play many small-board games and review every corner fight you lose.
