In this interesting and beautifully illustrated account of the Japanese tattoo, the authors' intent is to place the subject within a context more culturally meaningful than that usually given it.
Hence the title. The lofty samurai ethos is not usually associated with the lowly tattoo (and certainly no samurai was ever tattooed), but the "idealized self image" common to both allows for "the similitude between tattooing and the samurai life (that) runs on a moral and ethical level." Both demand both patience and diligence, as well as great skill.
Certainly fidelity, loyalty and determination were ideals for both the samurai and his plebian counterpart, the "otokodate." This was the chivalrous and gallant commoner who, with the political decline of the samurai, took his place in the popular imagination -- and was often tattooed. Originally a guild mark (among other things), the tattoo also decorated members of such heroic organizations as the Edo fire department, and even now I would guess that more sushi chefs (still manifest as a guild) sport tattoos than do yakuza.