Did I say 90%? Well there is more. This book by Feliks Hoff (kyoshi, 6-dan) (Originally Kyudo: Die Kunst des japanischen Bogenschießens) provides a wealth of detail on history, equipment, the hassetsu, and problem-solving and is in most cases an excellent reference. Personally I find it easier to follow the instructions in other books, then go to this one for details as desired. The book is interesting in that it presents kyudo from the Heki-ryu point of view, so there are differences here and there that provide food for thought and experimentation.
For example, Heki-ryu apparently uses the shamen uchiokoshi exclusively, so the shomen form is dealt with only in passing. Yet even for someone who uses shomen, the discussion of uchiokoshi is valuable, and helps to make one more aware of the important points of tenouchi. The main problems with the book are that the English translation is sometimes a bit awkward and, at least in the edition I have here, the quality of photographic reproduction is poor, so it is impossible to make out some details. Thus, when the book attempts to explain in words what would best be conveyed by an image, both may be found lacking.
Still, chapter 13, on solving common problems is excellent. This chapter is actually not by Hoff, but is a translation of one part of Inagaki Genshiro’s (hanshi, 9-dan) Kyudo Nyumon. It treats a vast number of common problems in far greater detail than any other book I have seen in English or Japanese.
On the other hand, the book (the original manuscript dates from the 1970’s) may be showing its age. In particular the chapter on examination form contains many errors and should not be relied upon. I do not know if these errors are long-standing, if they result from translation problems, or if the examination form itself has simply changed since publication of the original text. Japanese books and the current Kyudo Kyohon are better sources for the correct procedure in general, but there are so many details that participation in a live tutorial is really important. Likewise the chapter on competition form may have limited applicability outside of Heki-ryu competitions.
Still, I think this book is valuable for practitioners of any school. Perhaps the only caution, besides the ones noted above, is that those accustomed to other forms should be careful not to be confused by differences of opinion or methods. Such differences occur everywhere and are good, but it is nevertheless usually best to have a solid basis in your own school before branching out too much. Thus unless you are currently practicing Heki-ryu, it might be better to save this book until you have a few years of experience.
But whatever you do, don’t skip the fascinating, but unfortunately abbreviated, essay, Yumi no Kokoro at the back, by Inagaki-sensei. The full essay can be found in German here.
This book is published by Shambhala and should be easy to find. It looks like the US list price is $22.50. In Japan, ¥2,746.