Yanagi no Gosho Site, Archaeological palace ruins in Hiraizumi, Japan.

Yanagi no Gosho is an archaeological site in Hiraizumi, Japan, where a large palace once stood along the Kitakami River. Excavations have uncovered building foundations, defensive moats, and garden ponds across the grounds.

The palace was built in the late 11th century as the administrative and residential center of the Northern Fujiwara clan. It was destroyed in 1189 when Minamoto no Yoritomo's forces moved against them, ending their rule in the region.

The name Yanagi-no-gosho is not contemporary: the Azuma Kagami calls the residence simply Hiraizumikan, and the present name, set against that of the nearby Gara-no-gosho, was given in later centuries. The site is identified with the Hiraizumi residence of the Northern Fujiwara, and visitors can see reconstructed ponds, moats and roads in the park.

The grounds are mostly open to walk through, with paths leading across the excavation areas. A nearby museum displays artifacts and explanations that help make sense of what you see on site.

Excavations from 1988 uncovered a shogi piece and the Iwasaki-mura seal, the first such find in Japan, along with more than 10 tons of kawarake earthenware. The site was long thought to have been washed away by the Kitakami River before digs confirmed its location.