Shigisan Castle was built by Kizawa Nagamasa in 1536. Located at the top of Mt. Shigi (Odake), 437 m above sea level, it was a typical mountain castle of the Sengoku period, and functioned as a base for ruling over Yamato Province by controlling the road over the Shigi Mountains. The castle extends approximately 700 meters from north to south and 550 meters from east to west, making it the largest mountain castle in Nara Prefecture.
In 1542, Kizawa Nagamasa was defeated in the Battle of Taihei-ji, and the castle was burned down. However, Matsunaga Hisahide, who moved into Yamato Province, renovated it in 1559, building a large-scale fortress. In particular, a large five-tiered flat area was developed on the ridge on the north side of Odake. The enclosure at the northern end was called the Matsunaga residence in later times, which is considered to have been one of the most important parts of Shigisan Castle.
Shigisan Castle was the scene of many battles, including the fall of the castle in 1568 at the hands of Tsutsui Junkei and the allied forces of the Miyoshi clan, followed shortly thereafter by Hisahide’s recapture of the castle. Then, in 1577, Hisahide, who had rebelled against Nobunaga, was cornered in the so-called Battle of Shigisan Castle, and is said to have taken his own life after destroying the renowned Kotenmyo Hiragumo tea ceremony kettle that Nobunaga had much coveted. Shigisan Castle was abandoned at this time.
Today, no castle buildings remain. However, the site itself has escaped destruction owing to its location within the precincts of Shigisan Chogosonshi-ji Temple, and the moat, earthen mound, gate ruins, and several flattened areas remain almost entirely intact. Shigisan Castle retains the appearance of a medieval castle enclosure, and is considered valuable in this respect.