The default typeface style in Japanese is 明朝 minchō ‘Ming Dynasty’, the style which is the equivalent of bog standard serif in Latin typography.

If you are looking for a bit more dressy appearance, there’s the 教科書 kyōkasho and 楷書 kaisho styles. The kyōkasho style is used in textbooks, and is a sort of “humanist” intermediate between the rigid minchō and the more naturalistic styles that imitate brush writing. The kaisho style is patterned after traditional woodblock printing, and it is still the platonic ideal of Japanese characters. For even more fancy stuff you can use a 行書 gyōsho ‘running script’ style, which emulates the fluid but careful writing of a skilled calligrapher. The gyōsho style is still readable but can be tiring for long runs of text.

If you have a short piece of text that is not really meant to be easily read but is instead more just artistic, you can go all the way to 草書 sōsho ‘grass script’. This can be nearly unreadable, so that the reader has to concentrate on some characters to make out exactly what they’re supposed to be. It’s the typical style of calligraphy you see on wall hangings of poetry and proverbs and the like.

You sometimes may have use for a 篆字 tenji ‘seal character’ style. This is based on the forms of characters used in 判子 hanko signature seals that are used instead of handwritten signatures. Their use outside of the hanko context, without red ink, often gives a very archaic feel that hearkens back to ancient China.

There is also the ゴシック goshikku ‘gothic’ style that is the Japanese equivalent of sans serif. It’s probably not appropriate for a book on samurai, except maybe for back-cover blurb stuff or in contexts where the print is particularly small and hard to read otherwise.

Other styles out there include handwriting, imitations of other scripts (Latin, Cyrillic, Hangul, etc.), and geometric stuff.

Browsing images using these various terms will give you a good idea about how the various styles appear and are used. Even if you hire a designer, the exposure to Japanese typography will be useful in reviewing the designer’s work.

One thing that annoys everyone is Japanese text set way too small or light in the midst of Latin text. This is usually done in an effort to make the Japanese text fit existing Latin layout, because Japanese characters have much higher height and depth. Accept that you have to have more leading for the Latin text, don’t punish the Japanese text by squashing it into unreadable oblivion.

James, thank you for such a detailed, lengthy reply. That is exactly the type of information I've needed.

James, thank you for such a detailed, lengthy reply. That is exactly the type of information I've needed.

James, thank you for such a detailed, lengthy reply. (I have been trying to post this for two days now, but the Typophile site keeps crashing on me.) That is exactly the type of information I've needed.