N Japanese mythology, the islands were created by the

brine dripped from a spear that had been stirred in the ocean

Explanation:

In Japanese mythology, the Age of the Gods is the period preceding the accession of Jimmu, the first Emperor of Japan. The kamiyo myths are chronicled in the "upper roll" of the Kojiki and in the first and second chapters of the Nihon Shoki. The reigns of Emperor Jimmu and the subsequent monarchs are considered the Human Age.