two-space extension

  Difficulty: Beginner   Keywords: Opening
[Diagram]

The two-space extension on the edge

A two-space or two-point extension (two-space jump along the third line) is often used to create a base for a group, and is the minimal base required to have a hope of creating two eyes on the edge. This is one of the most common formations in go.

Because of the proximity of the edge, a two-space extension on the third line cannot be cut apart by the opponent, without other stones nearby.

After Black approaches at B1, White retreats to W2 with a two-space extension (it skips two spaces).

Extending two spaces like this isn't quite as stable as the one-point jump, but it expands further, and may create enough potential eye space for White to live.

[Diagram]

Security of the two-point extension

Black cannot cut the two-point extension in this situation (should White choose to connect below).

[Diagram]

Other extensions

These other two-point extensions with one stone or both on the fourth line are also useful for developing groups with a base; but they are less stable than the two-point extension on the third line, in fighting positions.


See also:


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