Big eyes can be small in the corner

    Keywords: Life & Death, Tactics

One of the special properties of the corner is that big eyes become smaller, meaning the extra liberties they normally have become void or reduced due to the eye being in the corner.

No big eye  

We have seen in big eye liberties that a squared four eye space creates five eye liberties. Let's see what happens in the corner.

No big eye  

Even if White goes first, White falls two moves short: Black can make an eye inside White's big eyespace due to the special properties of the corner, giving atari. This way, instead of five liberties, White has only three.

No big eye  

Preventing the eye with W3 here makes matters even worse. If we take the B2-W3 exchange into account, White has two liberties.

No big eye  

Under normal circumstances, White has seven (8-1) liberties against Black's five. However ...

5 -> 4  

Black can exchange B1 for W2, because otherwise Black would make an eye in the corner. After the exchange, we see that White has three liberties (that is, 5 - 2) against Black's five. White is dead even if White has sente.

Important to notice that the white eye still has its quality as a big eye if there are shared liberties.

Big eye  

If the bulky five is positioned as in this diagram, it becomes a big eye again because now there is no way Black can make an eye in it. White wins this capturing race seven-to-five.

Six-point big eye  

Here too, we have to imagine the B1-W2 exchange before counting liberties. White: 8 - 2 = 6. Black: 6. The player who begins, wins the fight.

Again we must not mistakenly assume White has a six-point big eye with eleven liberties.

Big eyes can be small in the corner last edited by on February 14, 2015 - 15:45
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