In-yo and gogyo (five elements)

The The I-ching and Chanoyu article has more on this, need to read. Pull quote from Gengensai from that article:

The four-and-a-half-mat tearoom was originally modeled on the yin-yang five-elements system. It means that the entire universe is encompassed within that single room. One theory holds that the tearoom arose from the study of Zen, and that it derives from Vimalakirti’s ten-foot-square hut. This, however, is incorrect. As for its origins, it derives from the I-ching, the Book of Rites, and other texts. The tearoom is built facing south, since originally the rooms are to be built so that they receive light from the southeast. It goes without saying that in the midare kazari tea procedure one must use a tray decorated with the eight trigrams, but in all tearooms, you should make the eight trigrams your model. It is for this reason that the tearoom is to be constructed in such a way that the daisu sits in the north, with the trigram for north directly across from you. You should know that this is why one sits facing north when conducting a temae.

from Gengensai Chadō Sōsho

Also check out the book 茶の湯と陰陽五行 ISBN: 978-4-473-01634-8. Anh is currently reading this.

Why is Host called Tou (East)

From Anh:

Reira — 8:26 AM
Because in ancient china the precious guest come from the west (think journey to the west and stuffs, basically the west (india) was considered more civilized) so host are called east

Dario — 8:27 AM
so hosts are called east to put themselves lower than the guest?

Reira — 8:28 AM
Yep