A certain basic familiarity with the Warring States period of Japanese feudal history would be useful delving in this well researched study. The tale is dramatic and spicy (but not too spicy) in turns. This is not just the story of a single life (one without very much documentation for much of it) but a series of separate, but linked, dramas played out over the course of about 40 years. The author and researcher--the scholar--gives us a carefully weighed description of each piece of the story, a care much like the kind of private storytelling by the attentive proprietor of a Japanese inn who takes the trouble to visit each guest's room personally. Many photographs in the book of scenes from the life of the subject were taken 'by the author'! This speaks better than anything of the care that the author treats the material of the tale. 
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 One of my favorite stories from this book was the tale of the father of the subject, one of the only subjects in the Emperor's realm to possesses detailed knowledge of certain literary works--a valued scholar. When the Emperor learns that a siege of the castle in which the scholar has decided to return to in order to defend a friend endangers the life of this scholar, the Emperor orders special envoys be sent to the fighting with the instructions--"Save that man! He is the only one who knows about these books!" It practically brought tears to my eyes.