The confusion between U+2014 and U+2015.

On 9/28/2011 11:22 AM, Koji Ishii wrote:
>   I don't know how it was determined but EM DASH in Japanese and Korean legacy encodings are mapped to U+2015, not to U+2014.


Here is my theory:

The character 1-1-29 is listed on page 69 of JIS 0213:2000 as 
corresponding to “U+2015 EM DASH”. It turns out that U+2015 is actually 
HORIZONTAL BAR and that EM DASH is actually U+2014. This is clearly a 
typo and should have been “U+2014 EM DASH”, as the correct code point is 
used on page 458, and the correspondence with the name EM DASH is also 
visible on page 321. The connection between 1-1-29 and the name EM DASH 
is also visible in JIS X 0208:1997, page 45. Finally, 0213:2004 gives 
the proper correction (page 21).

I suspect that somebody built a mapping by reading JIS 0213:2000, just 
looking at the code points.

The practical bottom line, in any case, is that we need to treat 2014 
and 2015 as equivalent in Japanese contexts.

Eric.