安土城
A new era of castle construction began when the daimyo Nobunaga built Azuchi Castle from 1576 to 1579. Earlier fortifications of the Kamakura and Muromachi periods were crude large-scale structures; Azuchi, however, with rich ornamentation and a keep rising seven stories high, became the prototype for castle construction of the period. The style of Azuchi Castle marked a shift in the function of the castles from a place that was merely a fortress and military garrison to a political, cultural and economic center. The newer style castles functioned as home to the "daimyōs", his family, and his most loyal retainers. Because of the expense of building such a lavish structure, castles in the style of Azuchi, functioned also to highlight the power and prestige of the "daimyōs". These new castles were built of wood and plaster on a stone foundation. Generally the main keep or "tenshu" was positioned at the highest point, surrounded by a series of interlocking baileys with walls, small towers and pathways. Residential buildings were located in one of the outer circles. The "daimyō" conducted his business in the citadel.