Ichikishimahime (or Itsukishimahime) is a deity of water that appears in Japanese mythology. In the "Kojiki" (The Records of Ancient Matters), her name is written "市寸島比売命" and in the "Nihonshoki" (Chronicles of Japan) it is "市杵嶋姫命."
When Amaterasu challenged Susanoo to prove his good faith at Amanomanai (the 'ukei' of Amaterasu and Susanoo), five male and three female deities were produced from Susanoo's sword (the female deities are collectively called Munakata Sanjoshin), and Ichikishimahime is one of them. According to the "Kojiki," Ichikishimahime, who was also called Sayoribime no mikoto, was the second-born deity and was enshrined at Nakatsunomiya Shrine, part of Munakata Taisha Shrine (Munakata City, Fukuoka Prefecture). According to the main text of the "Nihonshoki," Ichikishimahime was the third-born, but the second addendum mentions she was the first-born, and the third addendum describes her as being born first with the name of Okitsuhimabime. At present, Ichikishimahime is the enshrined deity of Hetsumiya Shrine, one of the three shrines that make up Munakata Taisha Shrine.
Ichikishima' refers to 'Itsuki shima' (the island of worship), so 'Ichikishimahime' means 'female (goddess) of the island of worship'. Hetsumiya Shrine is not on an island, so the descriptions in the "Kojiki" and "Nihonshoki" that she is the enshrined deity of the Nakatsumiya or Okitsumiya Shrine are closer to the origin of the name.
She is also the enshrined deity of Itsukushima-jinja Shrine (Hatsukaichi City, Hiroshima Prefecture), and it is believed that the shrine name 'Itsukushima' is derived from 'Ichikishima.'
Later, Ichikishimahime was syncretized with the Buddhist goddess Saraswati (known in Japan as Benzaiten) and worshiped as Benzaiten through the Honji-suijaku theory, which holds that buddhist deities appear to the Japanese as Shinto deities.
Ichikishimahime is also enshrined, together with Tagitsuhimenomikoto and Tagirihimenomikoto, at the Nino Goden (the middle one of three shrine buildings) of Usa-jingu Shrine in Oita Prefecture.