This is the replacement blade for the Silky Yamabico (407-33), the double-edged Japanese pruning saw with large teeth on one edge and fine teeth on the other.
It's the same 330 mm (13 in) chrome-plated blade the saw comes with: large teeth on the main edge for the main cut, and fine teeth on the back edge for thinner branches and cleaner cuts. When the teeth dull, fit a new blade and keep your handle and sheath.
Katsuji Miyawaki founded Silky in 1919 in Kishi, Japan, under the brand Tamakitsune, and all of its saws took the Silky name in 1983. The company is now headed by Uichi Miyawaki, and its saws are made in Ono, Japan.