Gaikan-oshō is Ikkyū's primary teacher at Ankoku-ji Temple, overseeing the young monk's training and education. He frequently finds himself exasperated by Ikkyū's mischievous behavior and unconventional problem-solving methods, which consistently challenge traditional monastic discipline. As a senior monk, he embodies the formal Zen Buddhist institution within the temple hierarchy, responsible for guiding novices through their religious studies. His interactions with Ikkyū typically involve correcting the boy's antics, often inadvertently creating opportunities for Ikkyū to demonstrate his cleverness.