The width is about 65mm. The blade length is probably around 300mm. It's likely a salmon knife from HP. It has been lightly sharpened with a string buff. [Excerpt from another site] This is a Kasumi product (laminated knife) made by forge-welding steel and jigane, and is water-quenched. The steel used is Shirogami No. 3. It is also called an Usu-deba (thin deba) and is mainly used for cutting fillets. Instead of water buffalo horn, plastic (partially brass) is used for the handle, and the black finish retains hammer marks. Processes are simplified, such as not polishing, to reduce the cost. Wholesalers and fresh fish shops in the market often use this type of knife.