Tutorial on the Rules of Go
A small example game suffices to illustrate all the rules of Go.
|Play starts on an empty board, which is
a square grid of horizontal and vertical lines. This is a small one with
5x5 lines forming 25 intersections, or ``points''. The standard size is
19x19, while 9x9 is ideally suited to beginners. The object of the game
is to conquer a majority of the points on the board, either by occupying
or enclosing them.
|The two players, Black and White, alternate in placing a stone
of their color on an empty intersection. Black moves first. Stones cannot
be moved, but can be captured. The unit of capture is a ``string'': a group
of stones of one color that are connected along the board lines. A string
is captured when it has no more adjacent empty points, or ``liberties''.
Above we see four strings with 4 liberties each.
||After another four moves, we again have four strings with 4
liberties each. The center point is a liberty of all strings.
If black were to play there next, then the two black strings would
be joined into one big string with 6 liberties,
while reducing each white string to 3 liberties. Indeed,
that would be the best move by far for black, but this game is to take
a different course.
|The next ten moves are not an example of normal play but serve to set up
a position in which we can show all varieties of capture.
Note that each string now has only one or two liberties.
Strings with only one liberty are said
to be in atari. If the opponent occupies their last liberty, they get
captured. From now on we will see the players making the best possible
moves. Black had better not play in the center now as the
resulting string would be in atari and get captured by white.
||Instead, Black captures the white bottom string that had put
itself in atari. This capture provides black 19 with the liberty it needs
to exist on the board.
|The center still being the most important point on the board,
white wastes no time in occupying it. This puts Black's string above
in atari. With the top left corner stone also in atari, White threatens
to capture 2 strings at once. Black could now capture the top white stone,
but White would just play another stone at the same spot to recapture four
||So Black captures the other white stone and in turn puts the
big white string in atari. A play by White on the middle right would now
result in self-capture. (some other rulesets forbid such
suicide, but there are no compelling reasons to do so.)
|So White obtains another liberty by capturing at 22. Now black
and white could capture back and forth in the corner till eternity (a ``ko''
situation), were it not for the ``super-ko'' rule, which states that one
is forbidden to recreate an earlier board position.
(This same rule prohibited White from capturing black 19 back,
as that would recreate the position after Black 17.)
||Black 23 captures a white stone, putting two white strings in atari.
|But is then itself captured by white 24.
||Note that black 25 is not forbidden, since the resulting position differs
from that after black 23 by one black stone. White 26 is a clever throw-in.
|The capture at 27 costs Black an important liberty, which would
have allowed her to put white into atari. Now, neither side can approach
the other without self atari. Unable to expand their territories, both
sides now ``pass''. Passing is allowed at any time in the game. (even though
it repeats the board position:-)
The game is over when both sides pass consecutively.
||Like stones forming strings, adjacent empty points form
empty spaces. A space having only stones of one color adjacent to it is
said to be enclosed by that side (so a single stone in the middle of
the board encloses 24 empty points:-)
Black has 11 points occupied and 4 points enclosed, for a total of
15 points. White has 7 points occupied and only 1 point enclosed, for
a total of 8 points. The 2 remaining empty points border on both colors
and thus remain unconquered. Black wins the game by 7 points!
Congratulations! You have now learned the rules of this magnificent
Diagrams courtesy of cgoban.
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