According to one theory proposed by the Nihon Gogen Daijiten,[5] the term comes from the Japanese expression "Gain or loss is a matter of chance" (勝負は水物だ, shōbu wa mizumono da), where the literal meaning of the phrase "matter of chance", mizumono (水物), is "a matter of water". In the entertainment business, income depends on a large number of fickle factors like popularity among customers, the weather, the state of the economy; success and failure change as rapidly as the flow of water. The Nihon Zokugo Daijiten,[6] on the other hand, notes that the term may derive from the expression doromizu-kagyō (泥水稼業), lit. "muddy water earning business", for earning a living in the red-light districts or from the Edo-era expression mizuchaya (水茶屋) for a public teahouse.[citation needed]