The last of the five major ōji (smaller shrines along the Kumano Kodō) before Kumano Hongū Taisha, Hosshinmon-ōji marks the outer limits of the grand shrine's precincts and literally means 'spiritual awakening gate'. It's a small building, painted red, and has a stone torii.
From here it's a gentle 7.5km, mostly downhill hike to Kumano Hongū Taisha. Buses run from Hongū Taisha-mae stop to Hosshinmon-ōji (¥460, 15 minutes, seven daily April to November, five daily December to March).