Using the Button with Equivalence Scoring


Button Go is a form of area scoring that solves the problem of granularity by adding an additional -point play. In addition to a standard play or pass, a single player may also choose to take the "button" for a -point gain.

Equivalence scoring is a form of territory scoring that gives the same result as area scoring. To combine button go with equivalence scoring in the most direct way, it is only necessary to change "taking the button" to "giving the button." In other words, the button is given as a prisoner rather than kept by the player. The rules of equivalence scoring then apply as usual.

This simple adjustment works for the following reason: taking the button under area rules is points better than what would otherwise be a pass worth nothing. Similarly, giving the button in equivalence scoring is points better than giving an entire pass-stone, so the strategic effect is exactly the same.

If the button is similar in size and shape to a go stone, it can also be used in Japanese fill-in counting. Since as a prisoner it represents a -point loss, it only partially reduces the value of the intersection it is placed on, and therefore represents a positive -point value on the board. (Since the proper komi for button go is points greater than that used for Japanese rules, the komi in this example will be 6 + = 7)

W3 gives the button  

B2 takes the last dame, and W3 gives the button as a prisoner. B4 and W5 are passes and are also given as prisoners. Both players agree the black+circle stones are dead and can be removed, and one white stone was captured during the game. Since White already made the final pass, the score can be determined:

  • 28 points of territory + 2 prisoners + -point button = 30 points for Black
  • 23 points of territory + 3 prisoners + 7 komi = 33 points for White

White wins by 2 points

If using Japanese fill-in counting, black prisoners are filled into Black's territory, and white prisoners and the button are filled into White's territory. The stones are rearranged for easier counting, and the score is

  • 25 points of territory for Black
  • 20 points of territory + 7 komi = 27 points for White

White wins by 2 points

Area Scoring  

Button go with area scoring will give the same result. This time, White takes the button instead of giving it, and once dead stones are removed, the area score is as follows:

  • 28 points of territory + 15 stones = 43 points for Black
  • 23 points of territory + 15 stones + 7 komi + -point button = 45 points for White

White wins by 2 points

(Incidentally, this is the exact same result we would get with Japanese scoring and the usual 6 komi, and this is true for most games, which is a benefit of button go.)

Bill: Since, in equivalence scoring, White makes the last pass, giving up a pass stone, you can simply let White not give a pass stone if White makes the first pass. And reduce the komi by point.

See also

Using the Button with Equivalence Scoring last edited by tapir on April 29, 2018 - 14:03
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