Shirogami is a highly reactive carbon steel. It should be mentioned that extra care is required, as the core is not stainless and should be dried immediately after use. It will develop a dark patina with usage, but any orange rust should be removed with a light abrasive.
Tojiro was founded in 1953 in Niigata and have been making affordable, high-quality knives ever since. They are one of the largest knife makers in Japan. They utilize a variety of steels in their knives, stainless and carbon, and both traditional Japanese knives and Western style double bevel knives are available.