This is a slightly mysterious gear. The top sprung pivot is very reminiscent of Simplex, but the pulley cage with off-set pivot is perhaps more Huret. As far as I am aware, neither French brand made short cage pull-chain derailleurs that mounted on the chain stay. The guide pulley is also much smaller than the tension pulley.

As is usual with Sanko-sha the construction of this derailleur is impressive, with quality bearings in the pulleys, well finished pressings and good chrome.

____________________________________________

1. •Brand: Sanko-sha
   

2. •Country: Japan
   

3. •Date of introduction: 1951?
   

4. •Date of this example: unknown
   

5. •Model no: unknown
   

6. •Weight: 300g
   

7. •Maximum cog: 26 teeth?
   

8. •Total capacity: 16 teeth?
   

9. •Pulley centre to centre: 48mm
   

10. •Index compatibility: friction
    

11. •Chain width: unknown
    

12. •Logic: low normal
    

13. •Pivots: two sprung pivots
    

14. •Material: steel
    

0273/I