This is a vintage prototype folding knife made in Seki, Japan by Yasuo Imai circa 1950s. Featuring a synthetic handle with a matador design, it measures 5.25" closed. Yasuo was the father to one of Seki, Japan's finest craftsmen, Seizo Imai. After Seizo's passing, several vintage old stock models were found at his warehouse. This is one of these rare finds.