From everything I have researched, Edwin appears to have fudged their timeline quite a bit, claiming to do a lot of things years before there's any proof that any Japanese makers were doing it. I wrote something here about trying to reconstruct the exact timeline: http://www.heddels.com/2015/10/who-made-japans-first-jeans/
They may have imported some (low quality) selvedge denim in the 1960s because a lot of denim was still selvedge (at least on one side of the cuff), but no one made the slubby, selvedge denim Japan is famous for in any sort of serious quantity until the late-1980s. No Japanese companies made jeans-grade denim at all until 1973.
From everything I have researched, Edwin appears to have fudged their timeline quite a bit, claiming to do a lot of things years before there's any proof that any Japanese makers were doing it. I wrote something here about trying to reconstruct the exact timeline: http://www.heddels.com/2015/10/who-made-japans-first-jeans/
They may have imported some (low quality) selvedge denim in the 1960s because a lot of denim was still selvedge (at least on one side of the cuff), but no one made the slubby, selvedge denim Japan is famous for in any sort of serious quantity until the late-1980s. No Japanese companies made jeans-grade denim at all until 1973.