This is a hon-yaki (fully hardened) knife of unknown authorship. The steel type is unknown, but as you can see in the photos, it has a beautiful Fuji wave hamon (temper line). Full polishing and re-sharpening were commissioned from a Sakai craftsman (with nearly 70 years of experience, known for crafting rare collector's item hon-yaki knives). By sharpening it to a clam-shell blade (hamagiba), it achieves both sharpness and resistance to chipping. The craftsman is known for his thin sharpening technique. The hairline finish, compared to a mirror finish, reduces food sticking and provides a smooth cutting feel. It was re-sharpened this month and is unused. A box and an ebony octagonal handle are included. Please feel free to ask if you have any questions. Blade length (from the heel to the tip): 225mm Blade width: 47mm Weight: 140g (blade only) / 197g (with handle) Spine thickness: 2.65mm Handle: Ebony octagonal Accessories: Box