I wish only to see photocopies, facsimiles, or if possible, the original document as generated and issued in the field.
Only? I have been researching the AVG Flying Tigers for a bit more than twenty years, and I have never seen an
original AVG document!
The Japanese records, such as they are, are of course a) located in Japan and b) written in Japanese. You can apply to the National Diet Library for information on where to begin, but you will have to bring your own translator!
Accessible in the United States, but still requiring a translator, are such books as HINOKI Yohei,
Hayabusa sentotai cho Kato (Tokyo: Kojinsha, 1987) and Japan Defense Agency,
Nanpo shinko rikugun koku sakusen (Tokyo: Asagumo Shimbunsha, 1970). The first is a memoir by a 64th Sentai pilot who several times met the AVG in combat; the second is a history of air operations in Southeast Asia from best Japanese sources.
If you require English-language versions, then there are the ATIS documents that Rick Dunn mentions; various U.S. Army monographs, notably Tanaka Masa, "Burma Air Operations Record"; and a British intelligence study, "Japanese Air Losses, Burma Operation" available at the (British) National Archives.
Finally, there are the more popular histories, including my
Flying Tigers: Claire Chennault and His American Volunteers (HarperCollins 2007) and Christopher Shores et al,
Bloody Shambles, especially volumes 1 and 2 (Grub Street 1992, 1993). In a class by itself is HATA Ikuhiko, et al.
Japanese Army Air Force Fighter Units and Their Aces, 1931 to 1945(London: Grub Street, 2002), a translation (more or less) of a Japanese book similarly titled.
Blue skies! -- Dan Ford