Abstract
The Ichinomiya coast located at the south end of Kujukuri Beach is one of the most famous surfing spots in Japan. In particular, breaking wave conditions are appropriate for surfing in the area between No. 7 and No. 10 artificial headlands. In this study, the reason for the establishment of the Ichinomiya coast as a surf spot was investigated in terms of the wave refraction and diffraction effect of offshore reef.