called “standard bearers.” Beyond the central area to the north and west stretched the realms of the Daimyo who had recognized Ieyasu’s rule only after his victory in 1600. These lords were called “outer Daimyo,” and their control was the most difficult problem of Tokugawa rule.
Both categories of Daimyo were allowed virtual autonomy within their realms, but the Tokugawa worked out a careful system of checks and controls to prevent any of them from becoming a military menace to the new central authority. Severe restrictions were placed on the construction or repair of castles, marking the end of a century of castle building which has left many picturesque old fortifications scattered around Japan. Each Daimyo was forced to leave in Edo, as hostages, members of his own family, such as his wife and sons, and he himself was compelled to maintain a permanent residence there and to spend alternate periods in residence at Edo and at his fief. A close watch was kept at important barriers on the highways of the land to look for “women leaving Edo and firearms entering Edo,” for the departure of hostages or the smuggling in of weapons would have indicated a planned revolt.
Perhaps the most interesting measure taken by Edo to insure its control over the Daimyo was the creation of a group of officials known as metsuke, who acted on the one hand as censors in ferreting out cases of misrule and maladministration on the part of Tokugawa officials, and on the other hand as secret police spying on all men or groups who could be a menace to Tokugawa rule. The Edo government has the dubious dis-