This is a rare vintage folding knife blade from circa 1980s made in Seki, Japan for Rigid, by Seizo Imai. Seizo Imai was one Seki, Japan's finest craftsmen and most famous knifemakers of the modern era. His collaboration with Parker spanned nearly two decades. He made knives for Parker, Frost, Browning, Explorer, Compass, Condor, and many others, including his own brands Imax and Seizo Imai. His custom Loveless style knives are works of art. After his passing, several vintage old stock models were found at his warehouse. This is one of these rare finds.