Go - unity in diversity

    Tao gives birth to one, one gives birth to two,
    two gives birth to three, and three gives birth to all things ...

                 Lao Tzu “Tao de Jing”

    Let a hundred flowers bloom,
    let a hundred schools compete.

                              Qin Shihuandi

     
    Guo rules are simple, but simplicity ends where scoring begins. There are many really difficult situations that follow logically from very simple rules. I want to talk about the reasons why there is no single methodology for scoring points in Go. About the reasons due to which there are many different versions of the rules of this game.

    Stumbling block


    Perhaps the main source of disagreement is the question of what should be considered “victory points”? By and large, there are two approaches: in the Japanese version of the rules, the total number of points of the territory and captured stones of the enemy is used, in the Chinese - the area captured by the player. It should explain how the territory differs from the area .

    The player’s territory is called the free points of the board, from which, following only vertical and horizontal connections, it is impossible to get to the opponent’s stones. In the figure on the left, points of the black territory are indicated by triangles. In turn, the area captured by the player, in addition to the territory, includes all points on which stones belonging to the player are installed.

    It is important to understand that both the territory and the area are calculated after removing all the “dead” groups from the board. For each group located on the territory of the enemy, its status is determined . For example, groups with two eyes are recognized as “alive” and remain on the board, enclosing their own territory. Groups of stones that can be captured upon completion of play are recognized as “dead” and removed from the board (in the Japanese version of the rules, stones removed from the board are added to stones captured by the opponent).
     

    The figure shows the result of the position assessment by the KGS server(when playing according to Japanese rules). Captured stones are shown in translucent color. The result of the game is determined by the ratio of the number of points in the territory marked with small stones in the picture (including under the “dead” stones). You may notice that some of the free points are not included in the territory for any of the players. Such points (from which you can get to stones of different colors) are called "neutral" or dame .

    Obviously, when using the Chinese version of the rules, neutral points can bring additional points, since they increase the areacaptured by the player. In this regard, the game, according to this variant of the rules, provides for the players to fill in all neutral points in turn, until the end of the game. If a player skips a move without filling the remaining neutral point on the board, this point will be captured by the opponent (as a result, the latter will receive an additional point, possibly determining the outcome of the game). 

    The process of compulsory filling of neutral points can be a problem when playing with time control using the Penalty Point (PP) system. When using this agreement, each player who exceeds the limit of the main time will be awarded penalty points. There may simply not be enough time to fill all the neutral points (or filling them out will become unprofitable due to fines). SystemSecond Reading (RS) lacks this flaw. At the end of the main time, the player is allocated short periods of time for each move ( boehm ), which are quite sufficient to complete moves that do not require long deliberation. The total game time in this mode is not limited. Only the number of time intervals that can be exceeded is fixed.

    When playing according to Japanese rules, it becomes unprofitable for a player to “finish off” dead groups on his territory. In fact, the “killing” of such a group, in itself, will not add points, but you will have to spend at least one point of its territory, in order to pick up the group. Defensive constructions turn out to be just as unprofitable, but, in this regard, it is important to strike a balance - if the enemy manages to invade and build a “live” group, the losses will be much greater.

    An important disadvantage of the Japanese version of the rules is the possibility of scam in scoring. Correctly counting the territory at the end of the game is not easy, therefore, there is a technique to simplify the calculation. Immediately after removing the "dead" groups from the board, players place all captured stones on the enemy’s territory, reducing it in this way. After that, the stones, inside the territories, usually move, to facilitate the calculation.

    The wonderful Hikaru no Go series has great illustrationhow, using this procedure (and a little sleight of hand), you can slightly increase your territory, due to the territory of the enemy. Another possibility is toss additional stones to the number of taken. Hikaru no Go also illustrates this point .

    Neither life nor death


    As I said, before counting points, “dead” groups are removed from the board. Unfortunately, the status of the group is far from always determined unambiguously. In this book is an example of the party, which was formed during a "live" form with two "false eyes". The figure on the right shows how black can build such a form. If the blacks did not unite, surrounding the whites, both eyes would be "false." Guo does not tolerate dogma. As soon as we formalize some kind of observation, introducing simplifications into the real “picture of the world”, this game immediately gives us a surprise. Each form must be considered individually. Empirical rules of various kinds help to play Go better, but are not "ultimate truth." 

    Often, the question of “life and death” depends on the order of the course and this fact is another reason for the inconsistency in the rules. According to Chinese rules, “playing back” controversial positions is carried out without changing the order of the course, being, in fact, a continuation of the party. In the Japanese version of the rules, the status of each group is determined separately. The first move, in this case, is always performed by the player defending the group.

    The dependence of the "life and death" of the groups on the sequence of the move, in itself, is a problem that can lead to disagreement in determining the winner (especially in the Japanese version of the rules), but this is only part of the trouble. In some positions, groups are neither "alive" nor "dead." This situation is called " seki ", but before talking about it, you should talk about "".



    In this position, the player who succeeds in first surrounding the opponent’s group wins. The outcome of the fight depends on the turn order, since the number of“ respiration points ”of both groups is the same. Samai situations are quite common in the game and it’s important to be able to distinguish them from hopeless positions.

    Such a position more interesting. Regardless of the prioritization stroke, the player attacked the rival group, and the situation gets damedzumari (lack of "breathing points" of the group). The next course, the enemy destroys his group. Thus, the start of the Neva fight one to any of the players. It is one of the possible options Seki (a situation where none of the groups can not "kill" the other). More complex examples Seki consideredhere

    Points of territory surrounded by groups in a state of secrecy are another reason for disagreement. According to Japanese rules, they are not taken into account. In the old version of the " Inga rules ", introduced in order to rationalize and unify the rules of Go, it was proposed to divide the territory captured in secs between the players, in proportion to the number of stones surrounding it. Unfortunately, this rule greatly complicated the scoring process. Since 1991, according to the rules of Inga, only points of the territory in secs , completely surrounded by any one color , are taken into account .

    One of the consequences of using the Japanese scoring system is that the well-known positions of "life and death" are rarely played out to the end. Japanese rules stipulate a number of special cases governing the consideration of such positions. One illustrative example is the question of the status of the position of the Magari Shimoku in the corner of the board. In the center of the board, this four-point territory configuration is certainly lively, but other rules apply in the corner:



    In this position, only black can start a Co-fight , and if there are no Co-threats on the board, they will win this fight. According to Japanese rules, in the absence of Co-threats on the board (such as secaki, for example), a white group, in this position, is considered dead. Such a "system of precedents" simplifies the analysis of positions in the ESE , but it does not help much in cases not stipulated by it. Japanese rules allow the intervention of judges to resolve such conflict situations, but in the systems of rules that try to minimize judicial interference (such as the Inga system ), afterplay is always used.

    About the benefits of useless


    Here is another dogma that can be called into question - "suicidal moves are prohibited." And according to Japanese and Chinese rules, it is forbidden to perform moves that rob the last dame of a group of their color. This prohibition underlies the rules of Go, and indeed, such moves may seem pointless. In fact, who might need to destroy their own group? In fact, everything is not so simple.



    In this position, White feels quite comfortable. They can take two black stones at any moment, simultaneously forming a group with two “eyes”. But what happens if Black is allowed to destroy his group?



    White must react to this move! Otherwise, their group may be destroyed by blacks. This means that a useless, at first glance, move could well be used as a threat in the Co-fight. But more complicated situations are possible. In some cases, having sacrificed a small group, the player gets the opportunity to provide life for a larger group! Consider the following position:



    If "suicidal" moves are prohibited, the fate of Black is sad. White overtake them in samai and take away all the stones. Everything changes if Black is allowed to destroy a group of four stones:



    Black is able to bring the position to the state of secand, therefore, save the life of their group (although not having received any points for its territory). Such situations are rare, but it is a matter of principle! If a move can affect the status of “life and death” of a group, it is not worthless. Ing considers the prohibition of "suicidal" moves excessive, even in relation to groups consisting of one stone. In fact, when playing according to Chinese rules, a player, having completed such a move, does not change his position, but simply passes the move to another player. Such an action is equivalent to a pass - allowed in the Go.

    Look into the abyss


    Ko is by far the most complex concept in Go's rules. Why is this question important? Why should players persist in repeating moves over and over that lead to an endless cycle? Why can not I go elsewhere on the board? Just because it is unprofitable. Often, the status of “life and death” of a large group of stones depends on the result of the Co-fight. The prohibition of the repetition of a position forces one of the players to break out of the “vicious circle”, making a move that is possibly less profitable, but allowed by the rules. Thus, a greater tactical diversity is introduced into the game.

    The prohibition of the repetition of the immediately preceding position is easily implemented and makes it impossible to form short two-way cycles in the game. Unfortunately, this is not enough to solve the problem. The presence on the board of several forms of “short Ko” makes it easy to get longer cycles:



    Similar situations of double, triple (and so on) Ko are encountered quite rarely in real games, but there is nothing supernatural in their appearance. Another, relatively frequent position of the “long Ko” is the situation of “ Eternal Life ”:



    It is not profitable for any of the players to retreat from this sequence of moves, as a result of which the game can continue indefinitely. Obviously, you need to tighten the Ko rule! The superco rule can be formulated in two different ways:

    • Super positional - an unconditional ban on the repetition of a position, without taking into account the sequence of moves
    • Situational superco - prohibition of repetition of a position, provided that the turn of the same player’s turn

    Obviously, in the first of these cases, it is required to introduce an exception for a single pass, after which the position is also repeated. Superco's rule can be easily implemented in computer programs, but in tournament games, players have to monitor the possible repetition of a position. Different rules apply to repeating a position in different ways. In amateur games, this result is usually equated with a draw, in professional games - the game is replayed.

    The rules of Ingaan attempt was made to formalize, dividing Ko into "combat" (associated with resolving issues of "life and death") and "harassing" (certainly prohibited in the game), but it can hardly be called successful. To understand the Ko rule, in this interpretation, a sufficiently high qualification of the players is required. Inga’s simplified rules use the “positional superco” rule.

    The end and the beginning


    To complete the picture, it remains to consider issues related to the start and end of the game. Guo’s game traditionally ends with two consecutive passes of players. This sequence of moves means that none of the players sees a way to improve the position. The following is a determination of the status of the disputed groups and scoring. The devil, as always, is in the details.

    In 2002, during the European Championship in Zagreb, a conflict aroseassociated with an insufficiently clear definition of the order of completion of the game according to the rules of Inga. One of the players demanded the removal of the unconditionally “dead” group from the board, after the formal completion of the process of coordinating the status of groups (the second pair of passes). The referee’s decision was made in favor of this player, but the judge’s intervention in such matters was contrary to the spirit of Inga’s rules. The judge’s decision was appealed, which ultimately led to the adoption of the “Inga simplified rules” system, which more strictly regulates the game completion process.

    The start of the game is also associated with certain discrepancies in the rules. When playing on an equal footing, this is Komi- compensation with white glasses for the first move performed by black. Currently, various values ​​of this parameter are used from 5.5 to 7.5. There is a tendency to increase this value when playing professionals. The fractional value of the Komi is designed to make draws of parties impossible (in fact, unlikely, since it is possible to recognize a draw by decision of the judge).

    When playing opponents of various levels, handicap comes to the fore. A weaker player certainly goes first. If this is not enough to compensate for the difference in level, two approaches are possible. First, a negative Komi value can be used.(in favor of a weaker player). The second way is to place the handicap stones on the board before the start of the game. According to the rules of Inga, the location of the handicap stones on the board is not regulated. At the beginning of the game, White simply skips several moves, allowing Black to go to any free place on the board. Ing believes that this contributes to greater tactical diversity in the game. In the traditional Japanese and Chinese versions of the rules, the handicap stones are put on the board in a strictly defined order. 

    When playing according to Japanese rules, the handicap stones themselves do not bring extra points. When calculating points according to Chinese rules - the situation is different. Chinese and based on it rule options compensate for white glasses associated with handicap stones. Although according to the rules of Inga, as well as in the Chinese version, the area (and not the territory) is taken into account, compensation for handicap stones is not made.

    It’s hard to say which of the Go game rules is better. Each of them has both its advantages and disadvantages. In most cases, the result of a batch, regardless of the system of rules used, will be the same. The rules differ in nuances, sometimes very subtle, but sometimes these differences become significant (especially when playing professional players). Right hereYou can find a great dashboard for various rule options. Perhaps it will be useful to someone.

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