The No. 15087 is the replacement blade for the Z-Saw V-Handy 200 (No. 18411), the pocket-size folding kataba.
It's a 200 mm (7.9 in) blade, 0.50 mm thick with a 0.70 mm kerf, with impulse-hardened universal teeth at a 1.75 mm pitch (15 TPI). The front of the blade is rounded, so it starts cuts in tight spaces. When the teeth dull, 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.