DISRAELI DOCUMENTS
The cheeky chappy with the unfeasibly large chin is Uzawa Isamu who performs/performed under the stage Agō Isamu. He was a well known comedian in 1970s Japan, performing as part of a group called The Handers.
Jokes don't often translate well - so I will just explain roughly what is going on. In Japanese the phrase 'to stick out one's chin' means to look very, very, tired. Agō Isamu is here saying:
"No more chin sticking out!" The implication being that, with a Maruishi PC electronic gear system, you will never be very, very, tired.
My thanks go to Mike Hasebe at the Shimano Bicycle Museum for patiently explaining this to me.