Turtle Shell Go

What would it be like to play Go on a Turtle Shell grid?

To find out, the .json files here work at govariants.com.

To use them there:

• Go to govariants.com

• In “config”, choose a “custom” pattern

• Copy and paste the suitable JSON file for the desired grid size

The JSON files (images and discussion on which board to use below): 7x7 - 9x9 - 13x13 - 15x15 - 17x13

Note that one can only play on the vertices. Experimentation by others shows that a Komi of 6.5 is probably the best Komi to compensate for the first move advantage, regardless of board size.

The boards

Further discussion

The best discussion about Go on other boards is probably on this page.

To summarize that page, a Go variant where we have either three or four liberties per square is more tactical than normal square grid Go, while a variant with five liberties per point is more strategic then normal Go.

To play Go on a Turtle Shell board so each connection has three or four liberties, play in the trangles and squares. To play Go on a Turtle Shell board so each connection has five liberties, play on the vertices (the corners of each square/​triangle).

As it turns out, for grids large enough to make interesting Go variants, a given Turtle Shell grid has a lot more squares/​triangles than vertices. That in mind, different grids should be used for a game played inside the cells versus a game played at the vertices.

Let’s look at the number of squares in the three main Go variants:

Size    Number of vertices
9x9     81
13x13   169
19x19   361

And let’s compare that to the girds here in this directory:

Size    Cells   Vertices    Edge type
7x7     106     88          Round
9x9     186     150         Square
13x13   386     294         Square
15x15   498     368         Round
17x13   504     378         Square

(Clicking on the grid size is a hotlink to the JSON which govariants.com can parse)

Point being 7x7 is good for a quick game, rougly equivalent to 9x9 Go, either as a tactical game in the cells (triangles and squares) or a strategic game on the vertices.

9x9 is good for something roughly equivalent to 13x13 Go, again as a tactical game in the cells or a strategic game on the vertices.

13x13 is roughly equivalent to 19x19 Go when played as a tactical game in the cells. If played on the vertices, it’s roughly equivalent to 17x17 Go; this is the size used in Tibetan Go, which has 289 vertices, compared to the 294 vertices in this grid.

Both 15x15 and 17x13 make good games, roughly equivalent to full sized Go, when played as a strategic game on the vertices. 15x15 has different edge dynamics than the 9x9 or 13x13 board, so one can also play the 17x13 board to get the same edges as the 9x9 and 13x13 boards.

The 7x7 board has the same edge dynamics as the 15x15 board.