Deba is japanese traditional knife.
It is used for filleting a fish.
Also you can cut meat and chicken including thin bones without losing edge.
Carbon steel Deba knife is easy to oxidize, so good maintenance is needed.
But sharper than stainless steel knife, and easy to resharpen.
So this Deba knife is preferred by professionals.
Only one side must sharpen (sharpen the left photo)
To avoid oxidation: clean with hot water and dry quickly after using. and protect with a little oil.
It is an idea to save carbon steel knife. Oil of the book prevents oxidation.