Iwatsutsunoo (Ihatsutsunowo) is a god (god of Shinto) featured in Japanese Mythology. Iwatsutsunoo is described as 石筒之男神 in Kojiki (Records of Ancient Matters), and as 磐筒男神 in Nihonshoki (Chronicles of Japan).
In the Kamiumi-no-dan (the Chapter of Bearing Gods) of Kojiki, when Izanagi cut the god of fire Kagutsuchi, which had caused death to his wife Izanami, on the neck with his sword Totsuka no tsurugi, Iwatsutsunoo was born from the blood on the sword which dropped on the rock. Before him, Iwasaku (a god who splits a rock) and Nesaku (a god who splits a root) were also born from the same blood. There is a similar explanation about his birth in the sixth "alternate writing" of the Kamiumi no dan, Nihonshoki, and Iwatsutsu no onokami was alleged to be an ancestor of Futsunushi no kami. According to the seventh "alternative writing" of the same Chapter, Iwasaku and Nesaku gave birth to Iwatsutsu no onokami and Iwatsutsu no menokami, who in turn gave birth to Futsunushi no kami.
Tsutsu' in his name means 'the divine sprit of …'like 'tsuchi' in 'Kagutsuchi' and 'Nozuchi,' and so 'Iwatsutsunoo' means 'a male god of rock.'
However, TACHIBANA no Moribe interpreted 'Iwatsutsu' as 'a stone hammer,' a hammer used to beetle a sword, in accordance with his interpretation of Iwasaku and Nesaku as 'the power of a sword that splits even rock-roots.'