Ubigo (pseudo-toroidal Go) Go forum

8 replies. Last post: 2018-02-01

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Ubigo (pseudo-toroidal Go)
  • Luis BolaNos at 2018-01-30

    I think toroidal Go is a great idea but find it quite confusing to play. Ubigo is a related variant that I prefer.

    In Go, every edge point is connected to another two. In toroidal Go, every edge point is connected to another three. In Ubigo, every edge point is connected to all other edge points. It feels similar to games like Kropki and Rin, but, unlike in those, being connected to the edge of the board isn’t enough to make life. It just means it will take much longer for your group to get into trouble, but it eventually will, and you can’t use the edges to make eyes.

    On tiny boards, the game is guaranteed to end in a whole-board seki. On smallish boards, it’s about putting yourself on the strong end of an eye-vs-no-eye capturing race. On reasonably-sized boards, you get an involved struggle for center territory.

    I’d love to have this variant implemented here.

  • ypercube at 2018-01-30

    What do you mean with " In toroidal Go, every edge point is connected to another three"?

    There are no edge points in Toroidal Go and every point is connected to exactly 4.

  • Luis BolaNos at 2018-01-31

    As you know, another way to describe toroidal Go is to say that it is just like Go, with the exception that every edge point not in a corner is additionally connected to an edge point in a straight line perpendicular to the edge to which it belongs, and every corner point is additionally connected to the two closest corner points.

    (I should have said: “In toroidal Go, every edge point is connected to another three, except corner points, which are connected to another four”.)

  • ypercube at 2018-01-31

    I think you are still either confused or not describing it correctly.

    Every edge (not corner) point is connected to 3 other point (in normal and toroidal Go) and 1 more point is toroidal Go (which we can find with a straight line, perpendicular ..., that’s correct).

    Every corner point is connected to two other points (in normal and toroidal Go) and 2 more points in toroidal Go.

    So every point in toroidal Go is connected to exactly 4.

  • Luis BolaNos at 2018-01-31

    I think I’m describing it correctly. When I say “In toroidal Go, every edge point is connected to another three, except corner points, which are connected to another four”, “another three” obviously means “another three edge points”, and “another four”, “another four edge points”.

  • David Milne at 2018-01-31

    If you have a paper 19x19 go board and bend it into a cylinder so that the right side meets the left side, you would have an 18x19 playing area. Is that right?

  • Carroll at 2018-01-31

    Yes and if you connect top circle to bottom one, you get 18x18 toroidal Go board...

    @Luis, your description is correct but why speak of edges on a torus which is edge free? You simply have all points connected to its four cardinal neighbours, I don’t see the added value to make it more complicated?

    Is it a way to explain Ubigo, do you have pointers to its description?

  • Luis BolaNos at 2018-02-01

    Carroll, yes, it’s a way to point out how toroidal Go and Ubigo are related. But it’s also a valid way to describe toroidal Go, considering that you most certainly won’t play it on a real torus.

    I haven’t seen Ubigo described anywhere else.

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