INI
Japanese Castle Types - INI
Japanese castles are classified by terrain into hirajō (flatland castles), yamajirō (mountain castles), hirayamajirō (hilltop castles), mizujirō (water castles), and kojō (lake castles). Each type was built according to historical context and strategic purposes, with different balances between defensive capabilities and convenience. While mountain castles emphasizing defense were mainstream during the Sengoku period, flatland and hilltop castles developed as political and economic centers in the early modern period.
Japanese castles
castle architecture
history
Sengoku period
Edo period
architecture
[item.hirajo]
code=1
slug=hirajo
name=Flatland Castle (Hirajō)
description=Castles built on flat land, functioning as political and economic centers.
convenience=High
defense=Reinforced by water moats
era=Early Modern Period (Edo Period)
examples=Matsumoto Castle, Nagoya Castle, Hiroshima Castle, Nijō Castle, Yamagata Castle
[item.yamajiro]
code=2
slug=yamajiro
name=Mountain Castle (Yamajirō)
description=Castles built in mountainous terrain with solid defenses utilizing natural topography.
convenience=Low
defense=Extremely high (utilizing natural terrain)
era=Medieval Period (Nanboku-chō to Sengoku)
examples=Kasugayama Castle, Bitchū Matsuyama Castle (Castle in the Sky), Gifu Castle, Iwamura Castle, Takanori Castle, Odani Castle
[item.hirayamajiro]
code=3
slug=hirayamajiro
name=Hilltop Castle (Hirayamajirō)
description=Castles built on hills or low mountains in plains, combining advantages of both flatland and mountain castles.
convenience=Moderate
defense=High (stone walls + terrain utilization)
era=Late Sengoku to Edo Period
examples=Himeji Castle, Matsuyama Castle, Tsuyama Castle, Osaka Castle, Sendai Castle, Kumamoto Castle, Edo Castle, Marugame Castle, Azuchi Castle
[item.mizujiro]
code=4
slug=mizujiro
name=Water Castle (Mizujirō)
description=Castles built facing the sea, utilizing seawater in their moats.
convenience=Maritime transportation hub
defense=Strong against maritime attacks
era=Sengoku to Edo Period
examples=Takamatsu Castle (Japan's largest water castle), Imabari Castle, Nakatsu Castle
[item.kojou]
code=5
slug=kojou
name=Lake Castle (Kojō)
description=Castles built surrounding lakes or marshlands.
convenience=Water transport hub
defense=Natural defense using water
era=Sengoku to Edo Period
examples=Matsue Castle (National Treasure), Zeze Castle