The S-306 is the replacement blade for the Gyokucho ZA 240, a 240 mm craft saw for carpentry, joinery, furniture, instrument making and wood and bamboo crafts.
It has the same specs as the blade on the saw: 0.3 mm thick with a full metal back, teeth at a 1.5 mm pitch (16.9 TPI), a kerf of about 0.51 mm, and teeth that run around the curved tip so it can start a cut in the middle of a panel. It fits either handle, rattan (No. 306) or TPE (No. 307). 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.