DISRAELI GEARS
Sun-Bow is the brand of a company called Yamashita Iron Works Ltd. based at No. 36, Sambocho 4-cho, Sakai, Osaka Prefecture, Japan. The evidence for this is:
Two further pieces of relevant information are that:
It seems clear that SY derailleurs and Sun-Bow derailleurs were produced by the same company.
It's possible that Yamashita Iron Works Ltd. of Sakai is still in business today. The story might, possibly, be:
It is possible that Yamashita Iron Works Ltd. used the SY brand for designs that derived from Shimano models, and the Sun-Bow brand for designs that were inspired by SunTour. Or it is possible that the SY brand was used when the company was called Yamashita Iron Works Ltd., but when it changed its name to Koyo Giken Company Ltd. it also changed its brand to Sun-Bow. Both are guesses.
see also Japan's Bicycle Guide '56 1956
see also Japan's Bicycle Guide '56 1956
see also Japanese Patent # S54-57737 - Sun-Bow 1977
see also Japanese Patent # S54-57737 - Sun-Bow 1977
see also Japanese Utility Model # S54-67457 - Sun-Bow 1977
see also Japanese Utility Model # S54-67457 - Sun-Bow 1977
see also Japanese Utility Model # S54-69550 - Sun-Bow 1977
see also Japanese Utility Model # S54-69550 - Sun-Bow 1977
Sun-Bow - YA-100 label 1977?
Sun-Bow - YA-100 label 1977?
see also New Cycling 05/1981 - '81 Derailleur Collection
see also New Cycling 05/1981 - '81 Derailleur Collection
see also Koyo Corporation - web site 2019
see also Koyo Corporation - web site 2019