The Teishu 亭主, or "Master of the Pavilion" (for some reason Sekishu 席主 is not used here) is also known as "the East" or Tou 東. In modern Chinese it still means "owner; one who stands treat." In Zen practice, the Abbot or retired Abbot lived in the "Eastern Hall 東堂" and was thus known as "Eastern Hall." Even today, the properly built Zen main hall is known as the Abbot's quarters or Hojo 方丈. The classical size of the Hojo is about10 foot square which equals the size of the four and a half tatami room.
When doing temae the host has the guest on the right side. The guest might be seated on the left side, but then the temae is known as Gyakugatte.