"Crossing the Obo Gorge" Location: Oho Gorge, Miyoshi City, Tokushima Prefecture ＊ "Oho Koho Danger" is a valley of about 8 km long created by the torrent of the Yoshino River that crosses the Shikoku Mountains after 200 million years. Obo Gorge, which boasts a beautiful scenery that looks as if marble sculptures are rising, was designated as a nationally designated natural monument on March 18 2014 (Heisei 26) as a nationally valuable place where you can see the formation of the Japanese archipelago from the beautiful rocks and V-shaped valley that can be seen up close, and on October 7, 2015 (Heisei 27) it was designated as a national place of scenic beauty.