This light and easy-to-read stainless steel square is used not only as a framing square and scale, but also as an angle of inclination and try square. The blade is 15 mm wide, the standard measurement in Japan for tenons and board thicknesses. The front of the square has the usual deep-etched metric markings (mm). The back has two calibrations: one gives the diameter (x 3.14) and the other the length of one side of a square inscribed by that diameter (x 0.7). The bevelled edges and slight hollow grind prevent ink markings from being smudged. Accuracy 0.1 mm per 100 mm.