|The VeloBase History of Sankosha
founded by Mr. Kuno Nobutoshi, I think shortly after 1945. It was based
in Tokyo. The first derailleur, produced in 1947, was a double cable
type. I believe this was the first derailleur produced in Japan.
1951, I believe that Sanko produced a single cable pull-chain
derailleur, derivative of a Simplex design, with two sprung pivots. A
series of other designs followed throughout the 1950’s, including the
F-1 and F-2, which appear to be derivative of Cyclo designs, with a
sprung pivot and an unsprung pivot.
1963 Sanko produced their first parallelogram derailleur the PA, and
true to form, it was a quality item and was used by the Japanese
national cycling team at the Tokyo Olympics. They did also produce a
budget derailleur, the PF, which was a ‘flat plate’ design a bit like a
Huret Svelto or Shimano Pecker.
1965 Sanko launched the Procyon PV-I, an aluminium deraileur that was
arguably the most advanced derailleur in the world at the time. The
legend is that the cost of developing the Procyon derailleurs bankrupted
the company and it disappeared shortly after producing the Procyon
PV-III in 1966.