Life and death

Thirty knitting needles are connected in one hub, [forming a wheel],
but the use of the wheel depends on the emptiness between [the spokes].
Vessels are made of clay, but the use of vessels depends on emptiness.
Punch through doors and windows to make a home
but the use of the house depends on the emptiness in it.
That is why the usefulness of anything available depends on emptiness.

Lao Tzu " Tao Te Ching "


The stones in Go are the same and after installation on the board they cannot be moved. It seems that this is a simple game, but it is not. Simple rules lead to an unimaginable variety of tactical combinations. The problem of "life and death" is a good illustration of this.

Do not understand the sieve - do not play Go

The stones on the board do not move, but they can be removed from the board in whole groups (and only in this way). In order to "kill" a group, you need to completely surround it. A group in Go consists of an arbitrary number of interconnected stones (possibly from a single stone). Connected are considered stones located at adjacent intersections of the lines of the board. Since there are no diagonal connections in Go, in the figure on the left you can see a group of three black stones, almost surrounded by three white groups. Below this group is bounded by the edge of the board, which is a kind of “indestructible” wall.

The free intersections with which the group is adjacent are called “breathing points” ( dame ). The situation in which a group has only one dame is called atari and is an immediate threat to the group. If a player, being in such a situation, does not eliminate the threat, his opponent, by the next move, can close the last “breath point” and remove the entire group from the board. If the killed group is large enough, it can decide the outcome of the game. How can you eliminate the threat? The attacked player can “lengthen” by going to the last remaining dame. If such a move increases the number of "breathing points" of the group, the immediate threat will be eliminated, but this does not mean that the group will be saved.
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This tactical technique is called "ladder" ( sieve ). Once in this position, an inexperienced player may try to save a group of two stones, but will again and again fall into the position of atari. With each move the doomed group will increase and the threat of losing it will become more and more weighty. In the end, the "ladder" will reach the edge of the board and the whole group will be lost. But the sieve is a double-edged weapon!



In this position, on the path of the "stairs" was a black stone, which allowed the group to leave the environment. Moreover, after a failed sieve, blacks take advantage of white’s position and put double atari (something like a “fork” in Chess or Rendju). Whites can defend themselves only from one of the threats. One of the white stones will be removed and the black ones will break free.

Aesthetics of the screen is often used in Go problems. Here is an excellent example of such a task, mentioned in the book " Go and Eastern Business Strategy " by Miura Yusuyuki:

Give me a little, take a big one

Often, to destroy a large group of enemy stones, you have to sacrifice your stones. An example is a very beautiful position with the poetic name “Crane's Nest”.



Acting straightforwardly, black allows a group of whites to break out of the environment. The correct tactic in this position is to sacrifice one stone:



White takes one stone, but loses much more. This situation is similar to the one that arose in the sieve. Once in a hopeless situation, black had to sacrifice two stones, not trying to “pull out” the hopeless group. Sitho is a good illustration of one of the “ 10 Commandments of Go ”, associated with the name Honymbo Shusaku - “ If in danger, give without hesitation ” (another one of the “10 commandments” is in the heading section).

A group with two eyes lives, with one dies.

When the party comes to a close and the board is almost full, even very large groups can be completely surrounded. A group that has lost all dame will immediately die. But what will happen if you organize the "outlet" within the group?



In contrast to the possible (and as we have seen above, often justified) victims, “suicide” in Go is prohibited. The player, under his own power, cannot create a group devoid of a dame (strictly speaking, there are variants of rules allowing suicides of groups consisting of two stones or more, but suicidal moves by single stones are forbidden unconditionally). Such a dame, protected by its own group, is called the "eye." Is the presence of an “eye” a guarantee of the “immortality” of the group? Of course not (it would be too easy):



The fact is that the move leading to the removal of the opponent’s stones is not considered suicidal (this rule is called the “attacker's advantage”). The enemy has the right to fill the "eye", depriving the group of the last dame (and thereby killing it). But what if there are two or more such “eyes”?



Such a group lives even when completely surrounded! The enemy cannot fill the "eyes" in turn, since each of these moves will be considered suicidal. Of course, the “eye” has the right to close the player himself, but he will not do this if he does not want to lose the group. Once in a hopeless environment, the player should take care of creating an "eye" inside the surrounded group. This is what the last of the “10 commandments” says (“ If it is hopelessly isolated, choose a peaceful path ”), but it can be difficult to put it into practice.



These two groups are dead, because one of the dame “eyes” is not. The enemy can go into it, taking a part of the stones, after which the group with one “eye” will be taken on the next move. Beginners often lose groups of their stones, taking the false "eye" for the real one. By the way, two “eyes”, too, may well belong to two groups (this position is shown in the figure at the beginning of the article).

With false and true "eyes" is not easy to understand. Even more difficult are situations with determining the viability of groups containing territories consisting of several dame (such territories, inside groups, are also called “eyes”). Often, the life or death of such groups depends on the sequence of the move and can only be ensured by the correct sequence of moves. Tasks ( tume-go ) on the subject of "life and death" are very useful for development, since such situations occur in real games very often.

One of the best, in my opinion, problem books on this topic is the " Encyclopedia of Life and Death " by the authorship of one of the strongest players of our time, Cho Chikun . It does not need to be translated into different languages, since there is very little text in it. Using only different positions of Guo, the author consistently leads the reader from simple to complex, introducing more and more new concepts.

In all the tasks from this book, black is the first to go. Depending on the task (as a rule, it is easy to determine), their goal is either to build a living form (with two eyes) or not to allow it to be white. As a newcomer, it was difficult for me to solve some of these tasks in my mind (it has now become easier) and I began to translate them into SGF- format in order to be able to play all the options on the board. Those who wish can find the files here (without decisions, of course), however, I do not advise them to be abused. It is more useful to be guided in solving problems by the following approach .