Ballistol Universal Oil, in our experience, is the best oil to use for Japanese knives, both for the blade and the wooden handle. It is important to oil the knife blade from time to time, especially for knives made of high-carbon steel (e.g., blue and white steel), as these knives rust quickly if not properly maintained. Ballistol oil is fantastic! It is completely biodegradable, safe for skin and food. The oil is made from natural substances based on the anise herb (hence the distinctive smell) and is absolutely safe for humans and animals. Its use and natural decomposition will not pollute the environment. Ballistol oil is widely used for the care of guns and knives, but it can be used for many other tasks and surfaces - metal, wood, leather, rubber, synthetic materials, leather, animal hair and much more. Instructions for use: For high-carbon steel knives, we recommend applying Ballistol Oil with a soft, clean cloth after each use to prevent rust and protect the knife's surface. For rust-resistant knives (steels such as ZDP-189, R2, VG-10), we recommend applying Ballistol oil with a soft, clean cloth once or twice a month, depending on usage. Apply Ballistol oil once or twice a month to the wooden handle to protect the wood.