Alak

    Keywords: Variant

One-dimensional Go variant, with a change to the rules to the effect that filling in the final liberty of your own chain means that chain remains. That rule is attributed to Alan Baljeu. (See a posting of his to rec.games.abstract on 2001-12-30.) This is a quotation from that posting.

''A.K. Dewdney, in his book "The Planiverse" (a sci-fi book exploring the science of a 2D universe) mentioned a 2 player game called Alak[1]. Alak was described as go in 1D, but that doesn't work as a serious game. So I fiddled with the rules a bit and came up with something with surprisingly complex strategy. Rules:

  1. . Black and white alternate placing stones on a line divided into n points.
  2. . If placing a stone surrounds/outflanks stones of the opposite color, those stones are immediately captured.
  3. . It is illegal to place a stone where one was just captured.
  4. . The game ends when the player having the move cannot move.
  5. . The winner is the player with the most pieces on the board.''
[Diagram]

Legal or illegal?

[Diagram]

White lives ... for now

jsha: I haven't read the original source, but from the blurb in Planiverse it sounds like filling the last liberty of your own chain is not like making two eyes. IIf you fill the last liberty of your own chain, you are alive until you capture one of the adjacent (enemy) groups. After that, your opponent may immediately play under one of the captured stones to capture your group in a snapback. (W asks: Doesn't that break rule 3?) Note there is no ko here; in order to fill your last liberty, you must make a chain of at least 2 stones.

As far as I can tell, that is entirely correct. Watch the Alak Game 1 -- Migeru
[Diagram]

White captures

[Diagram]

White is vulnerable again

[Diagram]

Snapback

It seems to me that the moves above and below are a violation of rule 3 - pieces may not be played where one was just captured.Bezman
[Diagram]

White grabs one last Black stone

[Diagram]

White makes a solid, living group

... and then this allows White to make a chain that is not in atari, filling in the last liberty, thereby giving it life. Yes?

[Diagram]

Possible continuation. B+1

Modulo the legality of W4, of course. -- Migeru


Scartol: Okay, I'm lost. As far as I can tell, both W4 here and on the page for AlakGame1 are suicide, and therefore illegal. What gives?

You're probably right. But apparently suicide of more than one stone is not suicide but "making life". What gives? -- Migeru

HadouKen: It looks to me like W4 is not suicide because it both creates a chain (of one stone) and deprives it of its last liberty at the same time. So it's life.

Scartol: I hope this doesn't sound crass, but I'm lost and no longer care about all this intricacy. I've got my hands full with a new teaching job. If someone else wants to take my place in AlakGame1, feel free.


Sebastian -- Scartol has a point. The justifications and patches to the rules make the game quite unelegant - much unlike Go. Maybe we can preserve simplicity when we instead add one rule that says: Instead of a normal move, a player can choose to declare one eye (or maybe one field) as safe. If it is safe, nobody can place a stone there. (This mimicks the extra effort in building a second eye in 2D (regular) Go. We may define a marker for this - similar to a special stone. However, by contrast to special stones, it is not limited in number and can not used as an advantage of one player of the other. I like the idea of a "double eye" picture. -- 2003-09-20


Reference: article by Neto and Taylor in Abstract Games #13.

Alak Game 1


[1] See Alak0


This is a copy of the living page "Alak" at Sensei's Library.
(OC) 2014 the Authors, published under the OpenContent License V1.0.
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