Black Lotus said:
I'll do my best to find him! I am Japanese and all, should I try to find a color photo of him? And how big should it be?
A color image would be the Holy Grail.

But as I don't have an image at all as of now I'm really happy with anything... Should you happen to run across several images (preferably high-resolutions ones) just collect them and send them over to me, so I can toy with them to see which one is best. But for now anything will do.
Tech team images come at 96x96 pixels in any case.
For the record here are the COREd Japanese tech teams. Most of them I have covered (only Yoshiharu Iwanaka is the odd one out), but should you happen to run across better alternatives I'm more than welcome to consider replacing them. Just PM your email address and I'll pass along the stuff I got as of now. As I'm totally stuck to websites in English my sources are somewhat limited. For companies we/I try to get original logos in first and foremost, with images of the company or their main products a close second.
Kawanishi Kokuki KK, T1921
Takijiro Onishi, T1924
Diesel Motor Industry Co., T1925
Osaka Rikugun Zoheisho, T1926
Tama Army Technical Research Institute, T1927
Hidetsugu Yagi, T1928
Kawasaki Kokuki Kogyo KK, T1930
Yoshiharu Iwanaka, T1931
Kyushu Hikoki KK, T1934
Minoru Genda, , T1935
And thanks for your efforts, I really appreciate it!