Just finished reading this, and am finding it incredible that such customs could've existed. How much of the book is fact?
You may be interested in these threads:
http://www.reddit.com/r/AskHistorians/comments/2af74z/how_accurate_is_james_clavells_shogun_in_terms_of/
http://www.reddit.com/r/AskHistorians/comments/2iy8ec/ive_started_to_read_shogun_by_james_clavell_were/