Legend has it that the gai was invented during the Spring and Autumn Period (722-484 BC), but there does not seem to be any written proof of its existence until much later: "Confucius went walking in the rain without a gai."
民間傳說是春秋時魯國巧工魯班（公輸般）所發明，但史籍上卻無所記載。我們只能在西周姜太公所著「六韜」中看到：「天雨不張蓋」，及孔子家語中「孔子將行，雨而無蓋」。