The relationship between Kanbari Nyudo and little cuckoo is said to be originated in the fact that one of the kanji characters for the bird 郭公 (kakko) has a similar sound to 郭登 (kakuto) which represents a Chinese deity for toilet.
加牟波理入道とホトトギスの関連は、ホトトギスの漢字表記のひとつ・郭公（かっこう）が中国の便所の神・郭登（かくとう）に通じることに由来するといわれる。