Kitanosho Castle, Japanese castle ruins in Fukui, Japan.

Kitanosho Castle was a fortification built in 1575, now preserved as a public park where foundations and stone walls remain visible. The ruins occupy a central location and serve as the focal point of this open space, allowing visitors to walk through the former grounds and understand its original layout.

The castle was founded in 1575 and originally featured a nine-story tower that stood as Japan's largest defensive structure at the time. Years later, following military losses, the structure was destroyed, ending its role as a working fortress and leaving only the archaeological traces visible today.

The castle is remembered for Oichi, Katsuie's wife, who refused to flee in 1583 and died with him in the burning keep. Her three daughters escaped and married into the highest ranks of the era: Chacha became Toyotomi Hideyoshi's second wife and mother of his heir Hideyori; Hatsu married the daimyo Takatsugu Kyogoku; Oeyo married the second Tokugawa shogun, Hidetada, and was mother of Iemitsu.

The park containing the ruins is free to visit and sits near the railway station, making it easily accessible on foot. The site is best explored during daylight hours when the stone foundations and walls can be properly examined and photographed.

The keep is thought to have had nine stories, which would have made it the tallest of its era; few records survive because the castle stood for only eight years. The three daughters of Oichi who left before the fire married Toyotomi Hideyoshi, Kyogoku Takatsugu and Tokugawa Hidetada.