A fascinating subject OM. I have always been interested in Japanese aviation, but mostly in the 1930s and wwii. The earlier period sounds interesting.
At the risk of leading myself down yet another modeling trail, can you give us a little more history on this particular aircraft and Japan's use of foreign trainers during the post-wwi era? I was had not been aware that Japan used license-built French designs in the 1920s, but why not? Italy and Russia built Nieuports during the war!
Thanks for sharing this interesting project with us, and for expanding my horizons. 
. My build list just keeps getting longer! 
Regards,
Bob
I am far from expert on it, Sir, and was fortunate to lay hands on a copy of 'Arawasi' magazine, which had an article on the Ko-3 that went into some depth on it.
A French air mission to Japan in 1919 had great influence on the Japanese Army; so did the reports of several Japanese officers who had served with the Aviation Militaire in France during the Great War. Both the SPAD XIII and the Nieuport 24 were ordered from France; more SPADs than Nieuports but arrangements were made for the Nieuport to be built under license in Japan. The Nieuports were initially built with 80hp motors for training, but in 1922, deliveries of Nieuports with 130hp motors began, and these replaced the SPAD XIII as the front-line IJAAF fighter. I do not know why this seemingly retrograde decision was made. A fondness for manouverability is sometimes suggested, but favoring home industry strikes me as a likely reason, along with possible problems of continued availability (no one was making SPAD XIIIs any more) and servicing difficulties (the geared Hispano motor was notoriously fickle).
The Ko-3 was replaced as a front-line fighter in 1924 by the Ko-4, a license built version of the Nieuport-Delange Ni-D. 29. Six hundred of these were built, by Nakajima, more, I think, than were produced in France. These were still the predominant IJAAF fighter in 1931, when the Mukden Incident was contrived, and some saw combat use in Manchuria. The Nakajima Type 91 parasol and the Kawasaki Type 92 biplane replaced it starting in 1932.
Over this same period of the 1920s, the standard IJAAF observation/light bomber type was the Salmson 2, built under license by Kawasaki and by the Tokorozawa arsenal, to a total of at least six hundred, and possibly up to a thousand. These also saw much use as trainers.
The Japanese Navy took its air advice from the English, and a lot of its early equipment derives from the Gloster company. They did, however, employ the Hansa-Brandenburg W.29 two-seat monoplane float-fighter in quantity.
