The S-450 is the replacement blade for the Gyokucho Super Hard 270, a 270 mm kataba crosscut saw for carpentry: plywood, rough-sawn lumber, laminated board and stock 2 in and thicker.
It has the same specs as the blade on the saw: 0.6 mm thick with electroless nickel plating, and impulse-hardened crosscut teeth at a 1.7 mm pitch (14.9 TPI). With no back, it cuts to any depth, and it fits either handle, rattan or TPE. When the teeth dull, fit a new blade and keep your handle.
Gyokucho saws are made in Miki, Hyogo, by Razorsaw Kogyo, which was set up in 1969 when it developed the replaceable-blade saw. Gyokucho Sangyo, its sales company since 1975, sells them.