Zuishinmon 随神門 is the name given to the gate that was formerly known as Mt. Haguro's Niomon 仁王門 until the 1870s. It marks the start of the stone stairway of Mt. Haguro.
It was built during feudal Japan by a lord of a clan in Akita called the Yajima clan, who donated two Niô guards statues simultaneously. The Niô statues, because of their Buddhist origin, were removed from the inside of the gate in the 1870s; after the government ordered Dewa Sanzan conversion to Shintoism only. The Niô statues are now exposed inside Shozen'in Koganedo's exhibition room.
Also called "Kannagara no Michi" 惟神の道, Zuishinmon means "the path shown by the Gods that stayed the same since the ancient times."
To go there, get on the bus bound for Haguro-Gassan (bus timetable) and get off at Haguro Zuishinmon mae 羽黒随神門前.