Simply Wing Chun kung fu isbn 1861265964 is written in English by Sifu Shwan Rawcliffe from the UK and is recognised as a direct student of Yip Chun Sigung.
Rawcliffe explains Yip Man Wingchun from a basic and fundamental level. He describes in great detail the body structure and the energy in each movement e.g. Jum Sau, Bong Sau etc. There are many diagrams that would aid the understanding of most Wing Chun students. Of course this book is not a substitute for a good teacher but I think does help explain many of the reasons why we do certain movement. There is alot of content in this book and is one of the better books I have seen on Wing Chun in English.
I am sorry I wrote this in English but I do not now how to express this in Japanese.