ESP started as both a professional shop and a garage shop at Shibuya Tokyo in 1975.

Navigator Esparto seems to have been produced from 1975 to 1980.  A book of Hidesato Shino, one of the founder of ESP, tells us how the beginning of ESP was.  I got the catalogue of those days and became better at talking about ESP in detail than before.  But there are much unknown about ESP compared with the other companies.

ESP open old catalogues published 1980 and later to the public on their website. So the information of the products which manufactured in 1980 and later is sufficient. 1980 was a turning point of ESP when they directed commercial expansion to the world.  1975 to 1980 is mystery period of ESP because beginning of a company is always unstable and it is natural for them to change specification of products frequently.  Fortunately I got 1976 catalogue but later that was still unknown.

As far as my observation, there are some different specifications.

Headstock : Large & Small
Fingerboard : Maple & Rosewood
Finish : Opaque & See-Through
Joint Plate : 63mm×45mm(early probable) & 63mm×50mm(late probable)
Pole Piece Pitch : 10mm(early probable) & 10.05mm(late probable)
Rod Adjustment Bolt : Plus & Hex

This guitar has 63mm×45mm(early probable) joint plate and 10mm pitched pickups(early probable) which became tinged with yellow.  Outdoor photos was after change of bridge pickup to DiMarzio FS-1.

Concerning Esparto, I am still short of information. See-through finish, 3.28kg(includes strings). (Updated 2016.8.25).