«Meanwhile, let us have a sip of tea. The afternoon glow is brightening the bamboos, the fountains are bubbling with delight, the soughing of the pines is heard in our kettle. Let us dream of evanescence, and linger in the beautiful foolishness of things.»

21.IX La cerimonia del tèTea began as a medicine and grew into a beverage. In China, in the VIII century, it entered the realm of poetry as one of the polite amusements. The XV century saw Japan ennoble it into a religion of aestheticism, Teaism, a cult founded on the adoration of the beautiful, whose ideals reach their climax in the Tea Ceremony (cha no yu 茶の湯).

The Tea Room
In Japanese, the Tea Room is called sukiya (数奇屋). The original ideographs mean the Abode of Fancy, but latterly the various tea-masters substituted them according to their conception of the tea room, becoming the Abode of Vacancy or the Abode of the Unsymmetrical. It is an Abode of Fancy inasmuch as it is an ephemeral structure built to house a poetic impulse, Abode of Vacancy inasmuch as it is devoid of ornamentation, and Abode of the Unsymmetrical inasmuch as it is consecrated to the worship of the Imperfect.
In XVI century the formalities of the Tea Ceremony was instituted by Sen no Soeki, the greatest of all tea-masters, commonly known by his later name of Sen no Rikyū (千利休).
The early tea room consisted merely of a portion of the ordinary drawing-room, partitioned off by screens. The sukiya consists of the tea-room proper, designed to accomodate not more than five persons; of an anteroom (mizuya 水屋), where the tea utensils are washed and arranged; of a portico (machiai 待合), in which the guests wait until they receive the summons to enter the tea-room, and of a garden path (rōji), which connects the machiai with the tea room.
It is smaller than the smallest of Japanese houses, and the materials used in its construction are intended to give the suggestion of refined poverty: all this is the result of profound artistic forethought and the details have been worked out with care perhaps even greater than that expended on the building of the richest palaces and temples.
The tea room is not only different from any production of Western architecture, but also contrasts strongly with the classical architecture of Japan itself. The simplicity of the sukiya resulted from emulation of the Zen monastery, whose chapel is bare, except for a central alcove behind the altar,  in which is a statue of Bodhidarma, the founder of Zen Buddhism. The foundations of the tea ceremony  is dated back to the ritual instituted by the Zen monks of successively drinking tea out of a bowl before the image of Bodhidharma.
The guest, through the rōji, will silently approach, and, if a samurai, will leave his sword  outside, then he will bend low and creep into the room through a small door not more than three feet in height. This proceeding was incumbent on all guests and was intended to inculcate humility. The guests, entered noiselessly one by one, take their seats, first making obeisance to the picture or flower arrangement on the tokonoma (床の間).
The term, Abode of Vacancy, involves the conception of a continued need of change in decorative motives: the tea room is absolutely empty, except for what may be placed there temporarily to satisfy some aesthetic mood.  The simplicity of the tea room and its freedom from vulgarity make it truly a sanctuary from the vexations of the outer world. There and there alone one can consecrate himself to undisturbed adoration of the beautiful.

Artworks and flowers
The tea masters collected only objects which fell strictly within the measure of their individual appreciation and guarded their treasures with religious secrecy; it was often necessary to open a whole series of boxes, one within another, before reaching the shrine itself, the silken wrapping within whose soft folds lay the holy of holies. Rarely was the object exposed to view, and then only to the initiated.
When a tea master has arranged a flower to his satisfaction he will place it on the tokonoma, the place of honour in a Japanese room. Nothing else will be placed near it which might interfere with its effect, not even a painting, unless there be some special aesthetic reason for the combination. The flower rests there like an enthroned prince, and the guests or disciples on entering the room will salute it with a profound bow before making their addresses to the host. When the flower fades, the master tenderly consigns it to the river or carefully buries it in the ground. With the perfecting of the tea ritual under Sen no Rikyū, in the latter part of the XVI century, flower arrangement also attains its full growth, becoming an essential component of the aesthetic ritual.

Source: The Book of Tea (茶の本) by Kakuzo Okakura (岡倉 覚三)

·The Japanese tea Ceremony