The rule of the Tokugawa shoguns (1603–1868) coincided with the age of European intellectual ferment from which economics emerged as an independent discipline. During these two-and-a-half centuries, although certain branches of Western scientific thought were assimilated and propagated by Japanese scholars, the introduction of Western philosophical, political, and economic ideas into Japan was severely restricted. At the same time, though, the evolution of an increasingly complex Japanese economy was creating some of the phenomena which had inspired the speculations of European economic thinkers from Munn to Quesnay and Adam Smith. These phenomena included the expansion of commerce, the fluctuation of prices, and the growing sophistication of the division of labour.