Masakatsu Hamamoto (1905-1996)
He was the first Asian graduate of Harvard University as a Japanese immigrant in the US.
Until the war broke out, he served as a manager for Ford Motor Co in Manchuria.
During the war, he was asked many important roles by the army like official interpreter for Prime Minister Hideki Tojo, special adviser for Philippine President Jose Laurel and chief of the POW camp for the allied officers in Manila.
Hamamoto (left) with Yamashita(center) in Manila, 1945
After the war was over, he was sued as war criminal but liberated soon because his senior officer General Tomoyuki Yamashita testified that Hamamoto was originally a civilian merchant though he had a rank of army major. General MacArthur was interested in him later but it was too late to find him again. He could be a man who knew a lot about Japanese leadership during the war but spent the rest of his life as an ordinary businessman for Osawa Co (camera dealer) and Seiko Co (watch maker).
Therefore, there are few official records left on him but can be found a few which wrote about him in the internet like this.