Buitenland/ Extensions

Extensions

Quick reference to extensions on the third line from a single stone

Local context versus whole board situation

Invading extensions

• No surrounding enemy stones

Two Space Extension  

A Two Space Extension on the third line is an ideal extension because it cannot be cut and forms a base.

Two Space Extension  

Cannot be cut: tries to cut, blocks.

Two Space Extension  

Forms a base
DefendingABaseOnTheSide
BasicLiveShapes
SmallestGroupWithTwoEyes#toc3
BasicLivingEyeShapes
FourDieButSixLive on the third line
Six Die But Eight Live on the second line

Three Space Extension  

A Three Space Extension on the third line forms a base is faster but has a defect at a.
InvasionOfThirdLineThreeSpaceExtension

• Within the context of strong surrounding enemy positions(1)
  

((1)a 4473 enclosure on the left and 34PointLowApproachKeima)

A Two Space Extension on the third line is considered the ideal extension.
A Three Space Extension on the third line is faster but has a defect.
A Four Space Extension on the third line is too large and can be invaded.
A Five Space Extension obviously, can be invaded too.

Two Space Extension  

Maybe the marked stone is not needed for these examples.

Three Space Extension  

This diagram comes from Graded Go Problems For Beginners Volume II

Four Space Extension  

Five Space Extension