The original Kannon-do was built in 951, but was lost to fire during the Onin War. The present building is a reconstruction from the 17th century. Kannon-do has a hip-and-gable roof covered in tiles, and is a rather tall structure for a building from the early Edo period. The principle image enshrined within Kannon-do is the Thousand-Armed Goddess of Mercy (Thousand-Armed Kannon) and the inside of the building is painted with colorful images of Buddhist deities.
It is a little difficult to gauge the size of the building from this picture, but imagine a person standing next to the building with their head coming just over the height of the railing and it will give you a better idea of the size. Kannon-do is usually closed to visitors, but the next time it is open to the public you can expect a post about it on this blog!