Genbu Ravine (玄武の沢 Genbu no Sawa) is a ravine named after the legendary tortoise Genbu (玄武). Formed when Youkai Mountain was still an active volcano. The bottom is covered with hexagonal cracks so it looks like a turtle shell, and it is surrounded by six-sided cliffs. This bizarre rock formation was made when lava flowing from Youkai Mountain cooled and hardened. According to Symposium of Post-mysticism, it is home to some of the kappa.