Usuchaki (tea caddy for tea powder for thin tea) (薄茶器)
Usuchaki is a kind of chaki (tea utensil), used to hold powdered tea, and the term is used in contrast to koichaki, which refers to a ceramic chaire specially used to contain the powdered tea for thick tea. It is usually a lacquered, wooden, lidded caddy, although the term 'natsume' (a form of chaki) is often used to refer to usuchaki in general.
However, the custom of using these wooden tea caddy for thin tea started only in the Edo period, when the powdered tea for thick tea and that for thin tea came to be contained in different types of containers. It seems to be by that the wooden tea caddies were ranked lower than chaire, which features many 'meibutsu' (distinguished tea utensils), but the fact must be noted that they were originally used in the same way as chaire.
Major types
Zukiri tea caddy
Yaro tea caddy
Satsu tea caddy
Kinrinji tea caddy
Nakatsugi tea caddy
Fubuki tea caddy
Natsume tea caddy
History
Zukiri,' 'Yaro,' and 'Satsu' wooden tea caddies were the forerunners of natsume tea caddies, which appeared in chakaiki (the records of tea ceremonies) prior to the natsume tea caddy. Among the others, the 'kinrinji' tea caddy is regarded as the highest-ranked usuki (usuchaki) and treated as such, since the legend has it that it was created by the Emperor Godaigo.
The first natsume is said to have been one that Goro HANEDA, a nurishi (maker of lacquer ware and handiworks), presented to Juko, though this theory is questioned by researchers. This is because there is no historical document to support this, even though several old natsumes that are said to have been made by Goro HANEDA can be found in the Fujita Museum of Art and others. A reliable record is "Record of the Tea Ceremony at Tennojiya," which describes the tea ceremony given by Sotatsu TSUDA on October 5, 1564, on which occasion the caddy was used, but the date is much later than the period of Juko.
The present-day distinction of thick and thin tea was not clear until around the Azuchi-Momoyama period, and wooden tea caddies were initially also used for making thick tea (It is considered that thin tea was originally prepared to empty the residual in a chaki.)