Anyone have any info about Diastone?

I’ve learned that he company was in Japan and made guitars and other musical instruments from the mid-1960s. Not many details have surfaced. The latest confirmed date for guitar manufacture I’ve found is 1976, but if you have evidence of something later, please provide details.

They also made banjos (a six string) and ukuleles (Martin copies – I have an undated model), pics on my own forum).

Apparently they may have also sold re-labelled Takamine guitars and made guitars for Martin when the Martin workforce was on strike. One account says they were in the same factory as Ibanez. All reports say they were good quality instruments.

I’d like to know more about them can anyone help?