The reason why the master guest rooms were mainly square shaped rooms measuring nine ken (one ken is a Japanese unit of measurement equal to just less than two meters) along each side was that their shape was based on that of an Amidado (temple hall containing an enshrined image of Amitabha), which was built in an effort to create heaven on earth.
主室が、主に九間の正方形をしていたのは、この世の浄土を目指した阿弥陀堂に起源を持つという。