In regards to the last post mentioning the Azby Brown book, it IS excellent, but the subject of that book is the construction of a very important temple. The framing detailing given is specific to that and is far more elaborate than what would be typical for a smaller garage as you are planning to build. Unless you are intending to use the finest quality wood available and are designing with a 1000 yr. lifespan in mind, the structural and design rationale used for a temple would be overkill, IMO. The book also lists no design values for timbers, does not discuss the all-important 'kiwari', or wood proportioning, and omits quite a bit ofthe joinery more typically found in residences and smaller structures in general. Still, it is an excellent read on the philosophy, design, and methods of Japanese temple carpentry and I would highly recommend it, given the caveats above.
The same publisher, Kodansha, also has the titles "What is Japanese Architecture?" and "The Inner Harmony of the Japanese House", both of which are excellent references as well. There are a very few other books in English on Japanese timberframing, but still the most useful, I think, to your needs is the Nakahara book as I mentioned in the first post.