Azuchi-castle-style tenshu castle architecture

Timeline

1. 1561–1570Kinai and the provinces of Ōmi · KinaiBy the mid-16th century, daimyo widely adopted mountain-castle construction with stone walls, bailey zoning, and watchtowers (precursors to the small tenshu); after Nobunaga conquered Ōmi he controlled the key traffic hub of Lake Biwa, laying the technical and political groundwork for a tall tenshu castle embodying centralized authority.
2. c. 1576–1579Azuchi Castle · Ōmi ProvinceNobunaga ordered Niwa Nagahide to supervise the building of Azuchi Castle, erecting a seven-story tenshu on the mountaintop, with outer stone walls and gold-leaf ornamentation displaying authority; the castle grounds contained a government hall, shrines, and a townscape, forming a prototype castle town combining military defense, administrative center, and commercial settlement, later called the 'Azuchi Castle style.'
3. c. 1582–1598Osaka Castle and the castles of Harima · Settsu ProvinceAlthough Azuchi Castle was destroyed, Toyotomi Hideyoshi inherited and enlarged the tenshu scale and stone-wall techniques in projects such as Osaka Castle and Himeji Castle; the Azuchi style became the standard architectural paradigm symbolizing the unified regime, its influence extending into the castle system of the Edo shogunate.