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Basic Eye Shapes HandoutBelow are examples of big eyes1. A and B marks the critical eye point. If a group has one eye point, life and death depends on which player plays at the critical eye point first. If a group has 2 or more critical eye points, then it is unconditionally alive.

Curved three Straight three.

L 4(alive) L 4 (L&D depends on who plays first. )

Note the marked stones for the L-4 diagrams. Sometimes the intersections of the big eyes need to be secured to be alive. In other situations, such as in the the curved 4 below, other intersections do not effect whether or not the group is alive.

There is also a ko that arises in the corner with the L-4 shape. This will be discussed in the 20kyu-8kyu study section.

Straight four T four Curved 4 (Note marked stone)

Square four (dead) Square four turn to curved three.

Square four is unconditionally dead. Any move that white plays turns white’s group into a curved three.

1 Sensei's Library defines a big eye as an eye of more than 3 spaces. http://senseis.xmp.net/?BigEyeLiberties A small eye is an eye that has not more than 3 spaces. http://senseis.xmp.net/?SmallEyeLiberties We feel that it is clearer to explain life and death by defining a big eye as any eye of more than 1 internal liberty.

Basic Eye Shapes 1/2

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Knife five (like a butcher knife) Rectangular-six shape Proper Response

Rabbity-six or Flower-six shape Proper response to White 2 Mistake: Double life (seki)

If Black plays at A, white is dead and black can play elsewher. However, if white responds with 2, black plays 3. White is dead because black can complete the T-4 shape by playing at A and B. Black should careful not to play at C, even after playing at 3. Black 5 leads to seki because after 5, A and B make live shapes (L-4 and curved 4).

Basic Eye Shapes 2/2