While sorting some thnigs out I found these pictures from the "Japan Grand Prix"
But unfortunately I do not know the year....!
On the first page you see Bill Ivy "roaring around the bend" as it says. His machine is a 125 (black number plate). Bill won the 125 cc class. Bill was followed by cameramen everywhere! On the bottom picture Hasegawa and Ivy are both on 250 cc Yamaha's. The 250 cc class was won by Ralph Bryans (Honda) and the 50 cc class by Mitsuo Ito (Suzuki).
On the other page it looks that Phil Read is writing down something, Mike Hailwood is very much at ease (he was going to win the 350 cc class) and Yamaha topengineer Naito-San is having Phil Read signing his contract (I think). The lower picture shows the very first Yamaha 350 cc racer, which was based upon the street YR-1. Tha racebike was called Z608 and had RD05A frontforks and front brake and a RD56 seat unit amongst others. The rider is K. Mimuro, who came home 3rd in the 350 cc class. Therefore this must be the 1967 event! Production of the standard YR-1 commenced in February 1967 and the race was in November.