| Position 1 | Position 2 | Position 3 |
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Taking into account the "no suicide" rule, let us examine what does it do to the concept of life and death of groups.
Point 1:
A stone cannot be placed in a suicide position unless it kills some enemy stones at
the same time (the "no suicide" rule).
and
Point 2:
If we can construct a group with such a shape that such move will
be impossible, this group will be unconditionally alive.
Cool! But how do we construct such a group? Lemme think... If the area enclosed by such group is divided into two separate "eyes", to kill this group the opponent would have to fill both these eyes - but this is not possible because by totally filling one eye he would have to play a "suicide move" - which is not allowed since this move could not have possibly kill the group since the second eye is not filled yet!
So - we have a basic concept of life and death - a group which has two eyes is unconditionally alive and cannot be killed! Well - actually there are some exceptions when the eyes are large enough so that the opponent can create a living (two-eyed) group of his own inside, but let us not dwell on this possibility for now. Important thing - two eyes cannot die!
Now lets look at some examples. In Position 1 of Fig 1-1 all the black groups are unconditionally alive and cannot be killed. The reason is that which cannot play at 'a' in each respective case because this move does not kill (the groups still would have the liberty at 'b' open) - and so it would be a suicide move explicitly forbidden by the rules. For the same reason, white cannot start by playing at 'b' in each respective situation - since the groups still would have the open liberty at 'a'. Position 2 is a little different, although here too the black groups cannot be killed. The difference is that while in Position 1 all black groups had only 1-space eyes, in Position 2 some eyes are larger. And so white can start the process of killing the black groups by approaching at '1' (or at '1' and '3') - but this is as far as it goes, and the same kind of reasoning can be applied to the remaining liberties at 'a' and 'b' as in Position 1. Black groups cannot be killed.
| Position 1 | Position 2 | Position 3 |
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For comparison, lets look at Position 3 of Fig 1-1. Here, the black groups do not have to separate eyes, and so they can be killed by the white sequence of moves as shown.
As stated above, a group which has two separate eyes cannot be killed. But you have to be careful - some eyes only look like eyes, but they are not eyes at all. Remember what we discussed about groups and stones being connected only if the are horizontally or vertically adjacent, but not diagonally adjacent? Well - this has to do with false eyes. Let us look at example in Position 1 of Fig 2-1. The black group looks like it has two eyes.... but careful! What if white plays at '1' in Position 2? Can he do it? Yes he can! The reason is that by playing at '1', white takes the last liberty of the marked black stone, and so kills this stone! Therefore, white's move at '1' is not really a suicide, and thus it is not forbidden by the suicide rule! Nest, white can play at '3' in Position 3 killing the whole black group!
| Position 1 | Position 2 | Position 3 |
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The reason the eye in Position 1 was false is that the marked black stone was not firmly connected (by a horizontal or vertical line) to the rest of the black stones - the connection was only diagonal, and so it could be cut by white! If the white marked stone in Position 1 was black, the black groups would have two real eyes and it would be alive.
Now let us look at some more examples of false eyes in Fig 2-2. In both situations, white move at '1' makes the black eye at 'a' false, thus killing the black groups. A black move at '1' would, on the other hand, make the eyes at 'a' real and ensure the life of the black groups.
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