Originally in the mythologies appearing in Records of Ancient Matters and Chronicles of Japan, the husband and wife deities Izanagi and Izanami, who were assigned with a job of completing the land formation, thrust Amenonuboko into the chaotic earth and stirred the earth with the halberd, and when they pulled the halberd up, a drop of the chaotic earth (or salt) which dripped from the point of the halberd turned into Onogoro Island (Kuni-umi; the birth of the land of Japan).
元来、記紀神話では、漂っていた大地を完成させる使命を持った伊邪那岐（イザナギ）と伊邪那美（イザナミ）の夫婦神が天沼矛を渾沌とした大地に突き立てかき回し、矛を引き抜くと、切っ先から滴った雫（あるいは塩）がオノゴロ島となったとされていた（国産み）。