Japanese Sword Choji Oil This is 4 oz. of Pure High Grade Japanese Choji Oil. Unlike some merchants, I want you to know how much oil you will be purchasing. Proven for centuries to protect fine steel weapons & all good quality tools against rust, corrosion and pitting. Only a small amount of this pure Choji Oil is necessary: just enough to lightly coat the whole blade is the correct amount to use. Packed & Shipped with Biodegradable Fill