Traditional Knife Japanese Higonokami Knife Handmade In Japan Hyogo Ken 9 CM, 9.5CM & 12CM Black. Handcrafted in Japan Black handle and double-edged steel blade Blade thickness: about 2.0~2.7mm Please note, carbon steel requires special maintenance: these blades blacken with use, oxidation is inevitable. Do not wash the knife, just wipe the blade after use. It is a good idea to regularly pass a cloth with oil on it.