These revenues arose in part from mines of gold, silver, copper, iron, tin, and lead, from timber, hemp, cotton, and silk, and from fisheries; but chiefly from the rice and other crops. There were no taxes or duties in Japan, except ground rents for lands and houses, payable in produce or money and in personal services. All these nobles had residences at Yedo, in the precinct of the imperial palace, in which their children resided as hostages for their fidelity. For each thousand koku of revenue these lords furnished on demand twenty foot-soldiers and two horsemen, and maintained them during the campaign, exclusive of the necessary servants and camp followers. The whole of their quotas, or of the feudal militia of Japan, thus amounted to three hundred and sixty-eight thousand foot and thirty-eight thousand eight hundred horse, in addition to a standing army of one hundred thousand foot and twenty thousand horse, maintained by the emperor from his own revenues, as garrisons and guards. The princes, however, prided themselves on keeping up many more troops than their regular quotas. To every five men there was an officer. Five of these sections composed a platoon, which had its commander. Two platoons made a company, which had its captain. Five of these companies, of fifty privates and thirteen officers, composed a battalion of two hundred and fifty rank and file, with its special officer; and ten battalions, a division of two thousand five hundred men. The civil division was much the same. Every five houses had an inspector, who kept a register of all births and deaths, and every street its magistrate and watch.