Ruins of the Former Sagami River Bridge (旧相模川橋脚)

After the Great Kanto Earthquake in September 1923 and its aftershock in January 1924, wooden pillars suddenly appeared in the rice fields in the Shimomachiya District of Chigasaki along the east bank of Koide River.  Raisuke Numata (沼田頼輔) (1867 ~ 1934), a historian and armorist, concluded these are the piers of a bridge over Sagami River, which is believed to have been flowing through the site from northwest to southeast (currently, Sagami River flows about 1.5 km west of the site between Chigasaki and Hiratsuka), built in 1198 by Inage Shigenari (稲毛重成) (? ~ 1205) to mourn the death of his wife.  In 1926, the site was designated as a historic site by the Japanese government.  In 2001, remnants of earth retainers were found north of the piers during further excavation.  These were also added to the historic site.

Monument of 湘江古橋行

Since the pillars are believed to have appeared due to soil liquefaction, the site was also designated as a natural monument by the Japanese government in 2013.

Today, the wooden pillars are preserved in concrete cases underground.  Concrete replicas are placed where the wooden pillars used to stand.

A stone monument engraved with a poem titled "湘江古橋行," written by Numata, was erected at the site in 1970.  The poem describes the origin of the bridge in classical Chinese.

The site is also known for its cherry blossoms during spring.