Hitohira Nakagawa Mosuke Blue #2 Kiritsuke 240mm Ho Wood Handle (Saya)

This is a carbon steel knife. Carbon steel is a non-stainless steel that lacks sufficient chromium and/or nickel to protect it from oxidation. As a result, it reacts to moisture and oxygen. While this may sound like a downside, it’s actually a key feature. Carbon steel forms a unique patina over time, is easy to sharpen, and offers excellent edge retention.
Caring for a carbon steel knife is straightforward and similar to other knives. Store it clean and dry, avoid using the dishwasher, and never leave it to air-dry. Also, steer clear of cutting extremely hard items like frozen food or bones. During use, it’s important to keep the knife dry—wiping it down with a cloth or towel is usually enough. If a carbon steel knife is not properly maintained, it can rust. While rust can be removed, it's best to prevent it from occurring.

There is no definitive "right or wrong" between carbon and stainless steel knives, but carbon steel is often considered superior for traditional knife-making methods. As a result, carbon steel knives generally offer better edge retention, sharpening ability, and overall performance compared to others in the same price range.
Please keep in mind that there are many types of carbon steel, just as there are with stainless steels, each with its own properties. Each should be evaluated on an individual basis.