The logo on this one is as the
logo on unknown model no. 1, which is probably a Matsumoku guitar. The
same logo is featured on the acoustic guitars which were made by
Matsumoku in the 1970s. The model
name is '501' and it was bought in December 1980. The guitar has been
examined by a luthier and the construction is apparently-
Neck - 3 piece Maple laminate
Back and sides - Maple
Top - Spruce
Fingerboard and bridge - Ebony, with synthetic mother-of-pearl inlays
Thanks to Fernando
Freitez for the pictures and detailed information