Odawara Castle Keep Museum

Odawara Castle Keep Museum is located within Odawara Castle, the historic stronghold of the Go-Hōjō clan (the Later Hōjō), the most powerful domain of medieval eastern Japan. For over a century, five generations of the Hōjō — Sōun, Ujitsuna, Ujiyasu, Ujimasa, and Ujinao — ruled from this castle before its fall to Toyotomi Hideyoshi in 1590. The present concrete reconstruction (1960) houses a well-organized multi-floor museum exhibition dedicated to the history, culture, and arms of Odawara Castle and the Hōjō domain.

From a nihonto perspective, the museum's most distinctive collection is its holdings of Sōshū-den (Sagami tradition) swords made by swordsmiths invited to Odawara by the Hōjō clan — particularly Yoshisuke, Tsunahiro, and Tsunaie, heirs to the Sōshū school established by the legendary Masamune in Kamakura. The Sōshū tradition is considered among the most prestigious in Japanese sword history, and the opportunity to examine works by its Odawara-period regional successors is rare. A special sword exhibition held in 2022 (Odawara Yukari no Tōken) further highlighted the depth of this collection.

Hōjō clan armor is also preserved in the collection, providing rich context for understanding the clan's century of military dominance and the sophisticated arms culture of eastern Japan's strongest medieval power. The adjacent Tokiwagimon SAMURAI-kan facility offers armor- and sword-specific interactive exhibitions including a projection-mapped immersive experience, making the entire Odawara Castle park a comprehensive samurai culture destination. Conveniently located approximately 90 minutes from Tokyo's Shinjuku Station and en route to Hakone and Atami, Odawara Castle is one of the most accessible castle and nihonto tourism destinations in the greater Tokyo area.