The Japanese Water Basin

The Water Basin or Chõzu-bachi is the symbol of purity, both in the physical and also the spiritual sphere, for here in the inner Rõji in which it is placed all the "dust of the world" is finally washed away and the devotee of Cha-no-yu enters another atmosphere. Hence it is the central point of this part of the garden. Moreover the Water Basin of a Tea-room is of a different kind from that used in ordinary gardens, in that it is placed low on the ground instead of on a pedestal. Hence its name "Tsukubai" or "Crouching Basin." It is the conventionalized form of a pool in some secluded valley into which run the mountain Japanese garden with Tsukubaibrooks. Here it is probably also a suggestion of the parable of Taoism concerning the greatness of a kingdom which says: "it is like a down-flowing rill, the central point toward which all the smaller streams under heaven converge." And to use this Tsukubai it is necessary that all, even the greatest of men, must stoop low on the ground, for "it is by humility that the true Sage is known."
The Water Basin is set on a supporting stone that should be visible above the surface of the ground if the basin is a low one, but should be flush with it if it be high. Its purpose is to give a firm base for the Water Basin which should be and appear perfectly steady and immovable. Though one usually finds a large Basin in a large Rõji and a smaller in a more circumscribed one, there are cases where a large one looks well in a small garden and vice versa, so that it is difficult to lay down any exact rule.
In front of the Basin and about two feet and a half from it, center to center, is the Front Stone, and to the left of this and about midway between the two is a rather small stone called the Candlestick Stone, while on the right side opposite is a larger one, the Hot Water Vessel Stone. The space between these stones and the Basin is cemented or pebbled and enclosed with an edging of stones or little stakes as is usual in water basins, and in the middle of this space a group of five round pebbles is to be placed as a splash breaker. Should the Water Basin be round then the Front Stone should be rather square in shape and vice versa.
The water basin is not well placed if it is too much in the shade, but it is even worse if there is none at all.
A stone lantern is often placed behind the Water Basin to illuminate it. Various shapes are used, as for instance the Enshu shape, the Oribe shape, the Michi shirube or Mile post shape or a variety of the Yukimi or Snow Viewing shape with the legs replaced by a low stone base, a simple rustic type of natural stone being preferred. In front of the lantern is a stone called the Lamp-lighting Stone.
A rather uncommon setting for a Water Basin is that called Koke Shimizu or Mossy Spring, in which a bamboo fence shaped like an opened two-fold screen is placed behind a Crouching Basin with a small shelf in the angle on which the dipper is placed.
A well with its attendant stones, the Water-drawing Stone in front and the Bucket Stone at the left side, may sometimes be found behind the water basin, and behind this again there may be a screen fence known as Yoroi-gata Sodegaki or Armour pattern screen fence. In other Tea-gardens the well forms a separate feature by itself beside the gate of the Inner Rõji.
The use of the Tsukubai or Crouching Water-basin was evidently not general at first, for when Ieyasu made one at Sumpa, Honda Masazumi remonstrated with him, saying that most people made their ablutions standing. Ieyasu replied that even the Shogun (Hidetada) would have to crouch down at this, much more any lesser person. (Tokugawa Jikki.) At the same period Oribe made a high basin in the garden of the Tea-room of the Shogun called Yamasato at Edo Castle. But in the days of Iemitsu the third Shogun, Kobori Enshu was ordered to remodel this garden and made the basin low. Iemitsu explained why he did so and Enshu said that it was made during the lifetime of Ieyasu so it was made high for his special convenience when he came to Edo. But since then all the Tokugawas have had low ones like anyone else. This answer pleased Iemitsu who was a great worshipper of his mighty grandfather.
-- from CHA-NO-YU, The Japanese Tea Ceremony, by A. L. Sadler,
pp. 29-32, © 1962 Charles E. Tuttle Co., Inc.