Resembling a shrine building, the main stage (hon butai) consists in a pavilion opened on 3 sides, connected with a wooden bridge (hashi-gakari) to the "mirror room" (kagami no ma), the place where the actors are preparing their entrance.
Today, Noh is still played on a traditional kind of stage, but the stages are usually located inside theaters. Really traditional Noh stages, located in open air like the one in this picture, are quite rare today.
This Nogakudo (Noh Theater) was built in 1881 in the Shiba Park, and in 1903 was moved at the Yasukuni Shrine.
EXIF info:
Nikon D90
Lens: VR 18-55mm F/3.5-5.6G
Focal Length: 18mm
Aperture: F/7.1
Shutter Speed: 1/50s
ISO Sensitivity: ISO 200