Found another:
An unusual 9-string guitar in which the G, D & E strings are in pairs (like the G, D & E strings on a 12-string guitar). The back and sides are not common wood or veneer, as can be seen from the pictures. Yamaha does not describe this as one of their guitars, suggesting it is very rare, or that the Internet lore indicating that Yung (or Young) Jin was a distributor who sold custom guitars from Yamaha in the 1970s is accurate. In any case, this guitar has been in a
large guitar collection for several years, and it has been played very little; it is excellent/mint condition.