I see the fancy W mentioned often and I asked the question several years ago myself. Can't recall now where I read the answer... but Nishiki was a contracted brand of West Coast Cycles. Look at the W logo again and I think you can see the W surrounded by two Cs. The first C is inverted.

I did just find a thread in which T-Mar also speculated the logo thing... but I know the place I first read it was not here.