Purpose of and rationale behind Go Markers U+2686 to U+2689

[Garth Wallace]

On Thu, Mar 17, 2016 at 9:18 PM, Garth Wallace <gwalla at gmail.com> wrote:
> There's another strategy for dealing with enclosed numbers, which is
> taken by the font Quivira in its PUA: encoding separate
> left-half-circle-enclosed and right-half-circle-enclosed digits. This
> would require 20 characters to cover the double digit range 00–99.
> Enclosed three digit numbers would require an additional 30 for left,
> center, and right thirds, though it may be possible to reuse the left
> and right half circle enclosed digits and assume that fonts will
> provide left half-center third-right half ligatures (Quivira provides
> "middle parts" though the result is a stadium instead of a true
> circle). It should be possible to do the same for enclosed ideographic
> numbers, I think.
>
> The problems I can see with this are confusability with the already
> encoded atomic enclosed numbers, and breaking in vertical text.

Correction: the 2-digit pairs would require 19 characters. There would
be no need for a left half circle enclosed digit one, since the
enclosed numbers 10–19 are already encoded. This would only leave
enclosed 20 as a potential confusable. There would also be no need for
a left third digit zero, saving one code point if the thirds are not
unified with the halves, so there would be 29 thirds.

And just to clarify, there would have to be separate half cirlced and
negative half circled digits. So that would be 96 characters
altogether, or 58 if left and right third-circles are unified with
their half-circle equivalents.  Not counting ideographic numbers.

This may not work very well for ideographic numbers though. In the
examples, they appear to be written vertically within their circles
(AFAICT none of the moves in those diagrams are numbered 100 or above,
although some are hard to read).