Our 70mm Tesshinsai Smoothing Plane is made by Yoshihiro Yamamoto using special high carbon #1 blue steel (Aogami Hagane) which is hand forged multiple times creating microscopic particles evenly distributed throughout the steel. This process gives a very sharp, long lasting edge. The steel is then forge inlaid on to a piece of soft wrought iron made more than 150 years ago. Mr. Yamamoto then heat treats and hardens the blade to RC 66. Finally it is sharpened to a razor edge and installed in a Japanese White Oak Body at 40°. Blade width is 2-7/8˝. Body width is 3½˝ and body length is 11¼˝.