God of the Sea - Oumi no Kami

…The significance of seppuku lies in breaking the peritoneum and releasing the small intestine, and when this is exaggerated, people may grab their innards and throw them away, as in the case of Murakami Yoshimitsu in the Taiheiki. According to legend, the first person to commit seppuku was a woman named Oumi no Kami, who, in anger and resentment towards her husband, cut open her stomach and released her intestines, but was unable to die and drowned in a swamp. It is said that even today, the crucian carp in the Harasaki swamp still lack five internal organs (Harima no Kuni Fudoki, Kamo District). Since then, seppuku has not only been limited to the samurai class, but has also been performed by townspeople, farmers, and women. …

*Some of the terminology that refers to the "God of Tanami" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…腹膜を破って小腸を出すことにむしろ切腹の意義があり，これが誇張されれば《太平記》の村上義光（よしてる）のように，はらわたをつかみ出して投げたりする。伝承上最初に切腹したのは淡海（おうみ）の神という女性で，夫に対する恨みと怒りで腹をさき，はらわたを出したが死ねずに沼に入水したので，この腹辟（はらさき）の沼のフナなどには今も五臓がないという(《播磨国風土記》賀毛郡)。その後も切腹は武士階級に限らず，町人，農民，女性たちによっても行われている。…

※「淡海の神」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報