Iwatsutsuo-no-mikoto is a Shinto deity associated with rocks and stone, appearing in early Japanese mythological texts such as the Kojiki and Nihon Shoki as one of the kami born from the primordial deities Izanagi and Izanami. The name, often paired with a related deity Iwasaku, reflects an ancient reverence for the enduring, unyielding nature of stone as a sacred element of the land. While some shrine traditions and local folk beliefs have linked this deity to matters of steadfastness in relationships, such associations are not part of the core mythological record and should be understood as later interpretive traditions rather than established doctrine.