A major Mughal reform introduced by Akbar was a new land revenue system called zabt. He replaced the tribute system, previously common in India and used by Tokugawa Japan at the time, with a monetary tax system based on a uniform currency. The revenue system was biased in favour of higher value cash crops such as cotton, indigo, sugar cane, tree-crops, and opium, providing state incentives to grow cash crops, in addition to rising market demand. Under the zabt system, the Mughals also conducted extensive cadastral surveying to assess the area of land under plow cultivation, with the Mughal state encouraging greater land cultivation by offering tax-free periods to those who brought new land under cultivation. The expansion of agriculture and cultivation continued under later Mughal emperors including Aurangzeb, whose 1665 firman edict stated: "the entire elevated attention and desires of the Emperor are devoted to the increase in the population and cultivation of the Empire and the welfare of the whole peasantry and the entire people."
