Transcript Go, Wei Qi, Baduk a game of strategy

China
Korea
Japan & others
Wei Qi, Baduk, Go
a game of strategy
Fred Hansen
The Official Fred
Spring 05
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Why play go?
• Fun
• Challenge
• Think differently
– not procedural
• A window to the orient
• Only one rule
Warning: It takes time to “get” go
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What does go look like?
• Board with 19 x 19 lines
• White and black stones in bowls
• On your turn, put a stone on an intersection
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What is the goal?
• Get the most stones on the board
– surround bigger empty space
– keep groups alive
• The game ends when
neither player wants to play
– there’s no more space to grab
• In practice not all intersections are filled
– when it is clear what color goes there
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How a game might begin
• Players take turns putting stones
black’s
potential
territory
– 29 points
white’s
potential
territory
– 38 points
• White is ahead
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How a game might end
• Neither player can gain points
Cannot be part of
an immortal group;
effectively dead
black’s
territory
– 35 points
white’s
territory
– 46 points
• White wins
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Could black do better?
• Second move too “low”
• Better to be higher; push white lower
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How does a stone die?
• A “liberty” is an empty intersection
adjacent along a line
• A stone without liberties is dead
– It is removed from the board
No liberties  dead
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So, what is a liberty?
• A stone’s total
liberties are
– its own, plus
– those of adjacent
same-color stones
• Empty intersections
count only once
Liberties for the black stones
4
3
3
2
2
2
1
2
3
3
3
6
When it is played, a stone’s own liberties
are checked after making any captures.
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One Rule: No repeat
The board pattern must not repeat
• A move is illegal if it leaves a board
identical to what it was ever before
• Hence: cannot recapture simple “ko”
If white captures,
black cannot
recapture on
the next turn
sometimes black
makes a threat,
white responds, &
black recaptures
a “ko threat”
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Immortality
• A group with two holes is immortal
Black could capture
only by playing in
both holes.
• The possibility of two holes is enough
If black plays b,
white plays a,
and vice versa
a
b
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“First capture”
• Goal – understand capture rules
• Method – play first capture
– First player to capture a stone wins
– 7 x 7 board makes it faster
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