Karl, have you seen the book Measure and Construction of the Japanese House by Heino Engel? It’s about $15 on Amazon.com.
I haven’t looked at it in years but remember it having tons of very clear architectural drawings. It has several 5 star reviews on Amazon , and you can “look inside the book” at the table of contents and the introduction etc, but, unfortunately, it doesn’t show you any of the drawings. Maybe these sorts of plans are widely available on the net now, but if not, It’s well worth the price.
Here’s the blurb:
“A remarkable classic work on traditional Japanese architecture and its general integrative quality, the order of space and form, the flexibility of partitions and room functions and other important or unique qualities. The author describes in detail, and with numerous architectural plans and drawings, the influence of the anatomy of the Japanese human body on traditional units of measurement and on house construction. This work is not simply a description of the features of the Japanese house, but “an invitation to probe the possibilities of utilizing this architectural achievement of the Japanese . . . in modern living and building,” according to the author, who further believes that the unique features of the Japanese house are better suited to serve as a pattern for contemporary housing than any other form of residential structure.”