Someone in Japan has modified his Strida’s handle bars and change the bike from single-speed to 5-speed by inserting the Miyata FM-5 into the original crankset.
The FM-5, of which the gear ratios are 1.00, 1.31, 1.59, 1.91 and 2.21, was a product of 20+ years ago by Shimano. The production of Miyata bikes only lasted for a short period in the 80s in Japan so used bikes are difficult to find now. The Japanese guy probably removed the FM-5 from an old Miyata bike and installed it on his Strida.
The Bridgestone F4 was also a product in the 80s in Japan using similar crank gears which provides 4 gear ratios of 1.00, 1.61, 1.79, and 2.00. Compared with the Miyata bikes, used Bridgestone F4 bikes are easier to be found in Japan nowadays.