Every culture systematizes natural phenomena in its own way. Consider the number of colors of rainbow. Before the early Edo period, Japanese belived the rainbow had either 3 or 5 colors, depending on wether the Chinese theory of "Inyo-Gogyo-Setsu" or the old European astronony was applted. Following Newton's theory on the 7 color rays of sun, though, the Japanese bigan to see 7 color bands in the rainbow.