Tales of the Tokugawa, Volume II : Bakemono Yashiki; Or, the Haunted House (Dodo Press)

"In 1590 a. d. the Hojo were overthrown at Odawara by the Taiko Hidyoshi, and the provinces once under their sway were intrusted to his second in command, Tokugawa Iyeyasu. This latter, on removing to the castle of Chiyoda near Edo, at first paid main attention to strengthening his position in the military sense. From his fief in Totomi and Suruga he had brought with him a band of noted captains, devoted to his service through years of hardest warfare. He placed them around his castle ward, from East to South in a great sweeping arc of detached fortresses, extending from Shimosa province to that of Sagami. Koga was the chief stronghold on the North, against what was left of the Usugi power."