Hiiro-Doo Kozuka Signed "Masayoshi" with NBTHK Hozon Tosogu
Kozuka made of hiiro-doo, it is rarely used alloy of very pure copper. Its literal meaning is "scarlet copper", also know as shudoo. Produced only from a second half of Edo period untill Meiji period. It was made by specialised shops in a time consuming way. That is why it was rather expensive. (Alloy description from "Tosogu Classroom" vol. 1, by Fukushi Shigeo, translated by Markus Sesko)
Nanako ground, carved in takabori and decorated with shakudo inlay and gilded elements.
According to certification theme of the kozuka is shrimp from Ise bay, which english name is spiny Japanese lobster.