Despite the many references that fly around the cultural strata, chanoyu, the Japanese way of preparing hot water for making matcha, is not ancient; it is timeless.
There is no consensus about how old "ancient" is, but it is clear that Western civilizations are pipsqueaks in comparison; so, the term is more a reference to way older than I am at this moment.
|Haniwa / Kofun Period, LACMA|
If you want ancient in Japan, you have to back to Japan's prehistoric Jōmon period (縄文時代 Jōmon jidai), from about 12,000 BC and in some cases cited as early as 14,500 BC to about 300 BC, when Japan was inhabited by a hunter-gatherer culture which reached a considerable degree of sedentism and cultural complexity.
Or hope to the Kofun period (古墳時代 Kofun jidai) is an era in the history of Japan from around 250 to 538 AD when things got a bit more organized and ceramic tomb sculptures, haniwa, appeared.
While the epitome of cultural complexity, the practice of growing in comparison, came to Japan from China (via Korea) about the 9th century CE with Buddhist Priest Yeisei who brought the first seeds, and two millennia later popularized by Priest Ikkyu . Would you call the Battle of Hastings "ancient"?
Nope, chanoyu is relatively new, but it enjoys a long, living tradition that is reflected in the posting by #Mamoru Fujiwara of these images from Kyoto.
Yakimono (ceramics) and okashi (sweets) are two aspects of the tangible culture of chanoyu in which we can appreciate a 500 year (give or take a decade) continuum of shape, material -- same type (rice, beans) or actually same (clay) -- as well as intangible qualities, how these are appropriated, handled, thematically assembled, etc.
To see these machiya (street-level stores common in Kyoto's older districts, with manufacturing and residential areas inside) with the kamban (store boards) and noren (entrance curtains), one could be back at lease in the 19th century. It all works the same. Add an electric light bulb ... it still works the same, but brighter perhaps (now the risk of electric fire threatens the structure whereas in the past it was only a charcoal cinder).
When I would go into "antique" shops in Kyoto, of course you see such things from the Meiji period / Victorian period, as a wind up grandfather clock or, from later times, golf clubs, electrified chandelier, etc. At least I can recognize one item's age from the other, a decade or two more or less.
I remember when I was in Suzhou China and purchased two small ceramic bowls (likely for rice) and was told they were Qing Dynasty. Sure they could have been from 1645, but more likely 1911 (or later). I couldn't imagine why I would have such an object that was so old. Venerable in my mind (and hand). I had no reason to want to make them older.
Thanks to Mamoru Fujiwara, my Facebook friend, for inspiring this posting.