The 1965 Sanko-sha Procyon PV-I and this model, the 1966 Sanko-sha Procyon PV-III were, in their time, the classiest and most advanced derailleurs in the world. They had aluminium knuckles and parallelogram plates (Campagnolo was still bronze), used Simplex’s double sprung pivots (which, in the absence of a slant paralellogram, gave a superior change to Campagnolo’s  single sprung pivot), had ergonomically placed adjustment screws, used a cunning mechanism which rotated the outer cable stop and the cable clamp in synch to stay aligned, had a pulley cage with an offset pivot and were beautifully made.

Europe, despite its confident assumption of superiority, had nothing to touch them - only the SunTour Competition was in the game, with a superior basic design, but less exotic execution. Unfortunately the expense of producing such a ground-breaking design allegedly bankrupted Sanko-sha.

I believe that the difference between the Sanko-sha Procyon PV-I and the PV-III was that the PV-III had the fancy variable rate spring and more ‘wrap’ on the pulley cage. I believe the PV-II was the same design concept manufactured in plastic - however I have never even seen a photograph (let alone an example) of this wondrous object.

Needless to say, even today Sanko-sha Procyons are highly prized in Japan and virtually unknown in Europe.

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1. •Brand: Sanko-sha
   

2. •Country: Japan
   

3. •Date of introduction: 1966
   

4. •Date of this example: unknown
   

5. •Model no: unknown
   

6. •Weight: 274g including hanger plate
   

7. •Maximum cog: 28 teeth?
   

8. •Total capacity: 26 teeth?
   

9. •Pulley centre to centre: 46mm
   

10. •Index compatibility: friction
    

11. •Chain width: 3/32”
    

12. •Logic: top normal
    

13. •Pivots: two sprung pivots
    

14. •Material: largely aluminium with steel pulley cage plates