The No. 30003 is the replacement blade for the Z-Saw Life Saw 265 (No. 30002), the traditional Japanese kataba with a rubber-coated pistol grip.
It's the same 265 mm (10-1/2 in) blade the saw comes with: 0.60 mm thick with a 0.92 mm kerf, impulse-hardened teeth at a 1.75 mm pitch (about 14 TPI), and electroless nickel phosphorous plating against rust. It comes off with a screwdriver, so you can fit a new blade and keep your handle.
Z-Saw's maker, Okada Hardware, has made saws in Miki, Japan since 1943 and was the first company in Japan to impulse-harden saw teeth.