Semeai: Capturing Races
A semeai is a capturing race: two neighbouring groups are each trying to capture the other, and only one can survive. These fights are decided by counting — whoever removes the opponent's last liberty first wins — and learning to count them correctly turns terrifying scrambles into problems you can solve.
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What a semeai is
When two enemy groups are pressed together and neither can make two eyes, they fall into a race to capture each other. Whoever fills the other group's final liberty first takes it off the board and lives. Because both sides are filling liberties, the winner is usually settled well before the last stone — if you can count.
Counting liberties
- Count each group's outside liberties — the empty points only that group touches.
- Shared liberties (dame between the groups) count for whoever fills them last, so they favour the defender.
- If both groups have the same liberties and it's your move, you usually win by playing first.
- An eye is a huge advantage: a group with an eye can often win even with fewer outside liberties.
Eyes change everything
The special case "me ari me nashi" — one group has an eye, the other doesn't — almost always goes to the group with the eye. The eye is a liberty your opponent can't fill until the very end, while your group can keep filling theirs. When you're in a semeai, look first for whether either side can make an eye; it often decides the race before any stones are counted.
Frequently asked questions
- What is a semeai in Go?
- A semeai is a capturing race between two adjacent groups that cannot both live. Each side fills the other's liberties, and whoever removes the opponent's last liberty first captures the group and survives.
- How do you win a capturing race?
- Count liberties. Add up each group's outside liberties, remember that shared liberties favour the defender, and note that an eye is worth extra because the opponent must leave it for last. Then fill in the right order.
- Why does having an eye help in a semeai?
- An eye is a liberty your opponent cannot fill until every other liberty is gone, so it acts as extra breathing room. A group with an eye often wins a race even against a group with more outside liberties.
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