JAPANESE KNIVES AND KNIFE SHARPENING
This is NOS (new old stock) Minamoto no Masakane hankotsu, there may be stains or rusting due to storage.
A Hankotsu is used for removing meat from bones, it works especially well with hanging cuts.
It is a mono steel knife made from SK, high carbon steel. Carbon steel knives are known for their sharpness, edge retention, and durability. They hold a sharp edge for a long time and are easy to sharpen and maintain. However, they require proper care to prevent rust and will “patina” after cutting highly acidic or alkaline foods.