Life and death

Thirty spokes join in one hub, [forming a wheel],
but the use of the wheel depends on the void between the [spokes].
Vessels are made of clay, but the use of vessels depends on emptiness.
Doors and windows are pierced to make a house,
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 de Jing " The
 

stones in Guo are the same and cannot be moved after installation on the board. This seems like a simple game, but it is not. Simple rules lead to an unimaginable variety of tactical combinations. The issue of “life and death” is a good illustration of this.

Do not understand shito - 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 this way). In order to "kill" a group, it is required to completely surround it. A group in Go consists of an arbitrary number of interconnected stones (possibly one stone). Connected are stones located at adjacent intersections of the board lines. 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. From below, this group is limited by the edge of the board, which is a kind of “indestructible” wall.

The free intersections with which the group adjoins are called “respiration points” ( dame ). The situation in which the group has only one dame is called atariand is an immediate threat to the group. If a player, in this situation, does not eliminate the threat, his opponent, in the next move, can close the last "breath point" and remove the entire group from the board. If the killed group is large enough, this can decide the outcome of the party. How to eliminate the threat? The attacked player can “lengthen” by going to the last remaining dame. If such a move increases the number of “respiration points” of the group, the immediate threat will be eliminated, but this does not mean that the group will be saved.



This tactic is called the “ladder” ( shicho) Once in this position, an inexperienced player may try to save a group of two stones, but will again and again fall into the atari position. With each move, the doomed group will increase and the threat of its loss will become more and more significant. In the end, the “ladder” will reach the edge of the board and the whole group will be lost. But shito is a double-edged weapon!



In this position, on the path of the "ladder" was a black stone, which allowed the group to leave the environment. Moreover, after a failed screen, Black exploits the vulnerability of White’s position and places a double atari (something like a “fork” in Chess or Renju). White can defend against only one of the threats. One of the white stones will be removed and the black ones will break free.

Shito aesthetics are often used in Go tasks. Here is a great example of such a task mentioned in the book of Miur Yusuyuki " Go and Eastern Business Strategy ":

Give small, take large

Often, in order 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 Nest”.



Acting bluntly, black allows a group of whites to escape from the environment. The correct tactic in this position is the sacrifice of one stone:



White takes one stone, but loses much more. This situation is similar to the one that arose in the network. Having fallen into a hopeless situation, Black should have sacrificed two stones, not trying to “stretch out” the hopeless group. Shicho is a good illustration of one of the " 10 Commandments of Go, " associated with the name Honimbo Shusaku - " If in danger, don’t hesitate to give"(another of the" 10 commandments "is placed in the section heading).

A group with two eyes lives, with one - dies.

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



Unlike possible (and as we saw above, often justifiable) victims, "suicide" in Go is prohibited. The player, under his own power, cannot create a group devoid of dame (strictly speaking, there are variants of rules that allow suicides of groups of two stones or more, but suicidal moves with single stones are absolutely prohibited). Such a dame, protected by his own group, is called the "eye." Is the presence of an “eye” a guarantee of the “immortality” of a group? Of course not (that 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 adversary 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 of these “eyes”?



Such a group lives, even being completely surrounded! The adversary cannot fill the “eyes” in turn, since each of these moves will be considered suicidal. Of course, the player himself has the right to close the eye, 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 the “eyes” inside the surrounded group. This is what the last of the “10 commandments” says (“ If you are hopelessly isolated, choose a peaceful path"), but to put it into practice is not easy.



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

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

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

In all tasks from this book, the first to go are blacks. Depending on the task (as a rule, this is easy to determine), their goal is either to build a living form (with two eyes) or not to make it white. It was hard for me, as a beginner, to solve some of these problems 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 (of course, without solutions), however, I do not recommend abusing them. It is more useful to be guided in the solution of tasks as followsapproach .