Fonts
Typesetters ordinarily use the Windows font MS PMincho (MS P明朝). Mac OS X users may use Hiragino Mincho Pro (ヒラギノ明朝). MS PMincho font sizes:
main text, block quotes (~ Brill 11 pt): MS PMincho 9.5 pt
appendices, bibliographies (~ Brill 10 pt): MS PMincho 9 pt
footnote text, indexes (~ Brill 9 pt): MS PMincho 9 pt
Other values compared with standard Brill type:
Brill 16 pt – MS PMincho 14 pt
Brill 14 pt – MS PMincho 12 pt
Marking Emphasis
Specify Bold Type
Mark emphasis in Japanese by specifying bold type. Because the default Brill typeface for Japanese, MS PMincho, lacks a bold companion, a different font must be used which has a bold character set. Presently the best choice HGMinchoE, a font which is bundled with Adobe InDesign CC2014.
HGMinchoE has the same type size specifications as MS PMincho.
Fake Bold Type Not Allowed
Never allow typesetters to use fake bold type: although applications like MS Word and even Adobe InDesign can produce such type using a crude algorithm, the characters look positively dreadful, and many Japanese characters actually become unrecognisable and thereby illegible because they get more or less ‘clogged up’ in the process.
Windows and macOS
Windows fonts, as long as they are TrueType fonts (.ttf) or TrueType Collections (.ttc), or CFF-flavoured OpenType fonts (.otf), can also be used on macOS.
Historical and Rare Characters
The matter of historical characters is still in flux. Many have already been added to the Unicode Standard but there will still be some that are lacking from the Standard and hence from available fonts.
Please also consult CJKV fonts: How to choose between them.