In 1961, Mazda bought the patent to Dr. Felix Wankel’s Rotary engine to begin prototype R&D. The Engineers quickly noticed scratches in the housings as a weak point in the design. They referred to these scratches as “Akuma No Tsumeato” ( 悪魔の爪痕 ) which directly translates to “Nailmarks of the Devil”. To combat this issue, engineers designed the rotors with the notorious apex seal.
8.5" x 3.5"