Pocket pens have already been mentioned in these chronicles. In the West, dare I say, they are known because of two models—the Pilot Myu 701 and its close relative the Pilot M90. However, there is a myriad of pocket pens in all colors, and materials and, to a certain extent, even shapes.
The Pilot Myu 25
A variation on this theme are the transparent Myu-25
I cannot say much more than this. I do not know how common or popular they were at their time in the mid to late seventies. Or if they were only intended as selling tools for the Pilot salesmen of the time, as was the case with the original demonstrator pens.
Those demonstrators on the pictures were manufactured in 1974 and 1975. Both have fine nibs.