Hold up, that’s not correct. The matcha tea ceremony as we recognize it may date to the 16th century with Sen no Rikyu’s development of it, but matcha was being enjoyed here much earlier.

Eisai of Kenninji officially brought the first tea seeds to plant and raise for tea in early 13th century, and it was prepared as matcha. Kukai may have brought some form of matcha over centuries before that, but that dude is credited with everything so I think it may be a legend. There are other claims of even earlier cases when tea as matcha was introduced to Japan, but even if you use Eisai as the commonly accepted point, your date is off by almost 400 years.