Hachioji Castle

Hachioji Castle, located in Hachioji City, Tokyo, is a medieval yamajiro (mountain castle) that spans the areas of Moto-Hachioji and Shimo-Ongata. Constructed during the Sengoku period, it served as an important military stronghold in the Kanto region and was a key satellite castle (shijo) of the Hojo clan’s main base, Odawara Castle. Built on Mt. Fukazawa (now known as Shiroyama) at an elevation of approximately 460 meters, the castle leveraged the mountainous terrain for formidable defense.

Origin of the Name

There are two main theories regarding the origin of the castle’s name:

1. Religious Legend: In the year 913 (Engi 13), the ascetic monk Myogyo, practicing on the mountain summit, reportedly had a vision of Gozu Tennō and eight princely deities. A shrine was built three years later in their honor, and the area became known as Hachioji (“Eight Princes”).

2. Shinto Connection: Another theory holds that the name comes from Hachioji-yama, named after the nearby Sannō-sha, a branch shrine of Hiyoshi Taisha. This interpretation is supported by the presence of a site called Sannō-dai within the current castle ruins.

Structure and Layout

The castle was carefully designed to match the surrounding topography and extended approximately 3 km east to west and 2–3 km north to south. It consisted of multiple zones:

• Fortified Area: The main keep (honmaru) was located at the summit, surrounded by multiple terraced enclosures (kuruwa) such as Matsunoki kuruwa and Komiya kuruwa, with additional forts and defensive structures.

• Residential Area: Mid-mountain, along the Shiroyama River, was the Ogosho-den (Lord’s Hall) and Ashida kuruwa, forming the castle's residential and administrative center.

• Nekoya Area (Castle Town): Located at the foot of the mountain, this area included:

  • Nakashuku (residences of samurai families)

  • Kajiyamura (home to swordsmiths)

  • Commercial districts such as Yokaichi, Yokoyama, and Hachiman Sanku, relocated from Takiyama Castle.

• Outer Defensive Forts: These included auxiliary castles such as Jofukuji Castle, Odano Castle, and Hatsuzawa Castle, forming a comprehensive defensive network.

Present Status

The Hachioji Castle Ruins are designated as a National Historic Site and managed by Hachioji City’s Cultural Properties Division. However, not all historically significant areas are protected due to complex land ownership—some parts, like the southern slope of the Taiko Kuruwa ridge, have become cemeteries or residential areas.

Despite the lack of complete historical records and limited budget, the site is preserved mainly in its ruined form, with no plans to reconstruct the wooden buildings such as the Ogosho-den. Nonetheless, many visible remnants remain even in areas outside the designated historic site.