Fonts for Shift_JIS
Shift_JIS art is the Japanese equivalent to ASCII art and is much more expressive due to the larger character set.
S JIS artworks are designed for MS PGothic (proportional Gothic) as it's the default font of Internet Explorer for Japanese.
In practice I've found that some artworks exist that are designed for MS Gothic (an earlier monospace version of the font) instead.
However this presents a problem when trying to showcase those artworks for a wider audience due to its dependency on a Windows-only font.
Mona is an open font designed for Linux that replicate the font metrics of MS PGothici, thus allowing displaying S JIS art without misalignment, however the stroke thickness and style differs enough that the artwork has a rather thick and posterized look to them that loses a lot of the delicacy of the original work.
As Mona is rather a large file for web use, a submona web font that was slimmed down to be used specifically to display S JIS art.
If you don't mind the increased size (and you shouldn't if you wish to display S JIS art correctly), the best option is the IPA Mona PGothic font which has been tweaked to better mimic MS PGothic. There is also an IPA Mona Gothic font for artworks utilizing MS Gothic.