Hundreds of castles, called yamajiro, were built as mountain watchtowers, in the Warring States Period (1467-1573). The castles were small, missing moats or turrets. Flatland-mountain castles called hirayamajiro, built on small hills, which still had good views of the areas being defended. From these castles, battles were conducted, government was administered and large armies were managed. The first hirayamajiro was Azuchi Castle, built by Oda Nobunga in 1579.