If I remember that all right, there were rumors that Tokai had another factory in Nagano as in "Tokai factory" early on, likely an oversimplification by people not familiar with how these things work in Japan. Why would Tokai build another factory 250km across Honshu island and have them make Tokais quite different from the Hamamatsu Tokais...for only a year or two, only for two models?
Later we learned that many of these guitars (only LS50s and Silver Stars IIRC) look internally and externally identical to Grecos from the same era that are commonly said to be Fujigen production, but we have no definitive documentation or proof that these particular Grecos were really made by Fujigen either, so we prefer to say "unknown factory..." - for the time being, and assuming that the factory was in Nagano prefecture we still say "...in Nagano")
Complications are that there were also ink stamped higher tier "real" Tokais prior (?) to the "Nagano" inkies and that not all inkies share all of the Greco traits - some look like 100% Hamamatsu, some have e.g .the Greco dowel tenon joint and volute etc. but a body with some or all of the typical Tokai routings. How exactly (who delivered parts to whom, who assembled them where...) these guitars came into existence is not known. The evidential similarities to Grecos is all we really have and all we can say for sure is that this limited line of guitars from that short era is different from the regular Tokais.
A plausible theory is that Tokai outsourced production of a few LS50 models due to high demand and the Hamamatsu factories working at capacity, but that's just a theory.
