So-do Hall (僧堂)
A so-do hall is a temple building dedicated to the communal living of practitioners (monks) and the promotion of ascetic practices. These halls are also known as "un-do" due to the presence of the monks, and also called "senbutsu-do" (lit. choosing Buddhism hall) after the fact that the practitioners have chosen a life of Buddhism. So-do halls are often found at Zen temples.
These halls usually function as places in which monks practice Zazen and take their meals, although meals are sometimes take in a separate shoku-do (dining hall) in Rinzai Sect temples. In such cases, the so-do hall is referred to as the zen-do hall.
Also, the training institutions in which monks must spend a certain amount of time training before they qualify as a chief priests in Japanese Zen Buddhism are known as senmon so-do (lit. specialist so-do halls).
Origin and history
During the Indian age of Buddhism, the collection of buildings in which monks lived was called so-do but this definition is now covered by the words a temple or monastery.
The form of so-do halls seen today is thought to have been established with the Shingi (daily regulations of Zen temples) founded in Tang Dynasty China by Baizhang Huaihai. A system was later developed by Chongsheng Temple on Mt. Xuefeng, Wanshou Temple on Mt. Jing and the temples on Mt. Tiantong. and this was later transmitted to Japan during the Song Dynasty.
The first so-do hall in Japan is believed to be that of Kosho-ji Temple (Uji City) which was established by Dogen, founder of the Japan Soto Sect. So-to halls went on to be constructed throughout Japan following the geographical spread of Zen Buddhism, and they continue to be used as places of ascetic practice at temples including Eihei-ji Temple and Kencho-ji Temple.
Location within the temple grounds
The so-do hall is one of the seven principal buildings considered necessary for a Zen Buddhist temple, and it is situated opposite the kuri (monks' living quarters) with the straight line consisting of the sanmon gate, butsuden (main hall) and hodo (lecture hall) between them, on the left when the butsuden is observed from the sanmon gate.
Exterior
So-do halls are generally rectangular in shape with a central entrance on one side. There are so-do halls with not one but two entrances where one entrance is opposite the other. The entrance does not have a door but generally just an opening. However, the doorway may be covered by a sudare (bamboo screen) or curtain during the summer and winter.
Interior
There is ordinarily a seated statue of a holy monk placed in the center facing the entrance. The Manjusri of Mahakasyapa incarnation of Gautama Buddha are chosen as this holy monk. It is strictly forbidden to pass in front of the holy monk statue. The 'tan' which serve as places for practicing Zazen and living space for each monk are arranged along the walls as if surrounding the holy monk. Each tan is the size of one tatami mat.
Where there is additional interior space, tan are placed in the central space at both sides of the holy monk statue.
The tan closest to the entrance is called the 'tanto' and is where the shiso (so-do hall preceptor) sits.
There are also instances in which tan, referred to as 'gaitan' (lit. outer tan), are arranged around the exterior wall of the building, whereas those on the inside are called 'naitan' (lit. inner tan).