Kasugayama Castle Ruins

Joetsu, Japan, Japan

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Kasugayama Castle Ruins are the remains of a famous mountain fortress in Jōetsu, Niigata Prefecture, best known as the stronghold of the legendary warlord Uesugi Kenshin during Japan’s Sengoku (Warring States) period.

Built on Mount Kasuga, the castle used the natural terrain for defense and became one of the most powerful and respected military bases in eastern Japan. Unlike many later Japanese castles, Kasugayama Castle relied mainly on earthworks, terraces, and dry moats rather than large stone walls.

The fortress spread across the mountain with numerous defensive enclosures, residences, and lookout points, forming an extensive defensive network. The castle was abandoned in 1607 after political changes in the early Edo period, but its remains are still well preserved.