A chaji is the most formal style of Japanese tea gathering, typically lasting around four hours and attended by three to five guests.
It usually includes a seasonal kaiseki meal, sweets, and both thick tea (koicha) and thin tea (usucha), with charcoal preparation (sumidemae) performed as part of the gathering.
Because both the host and the guests are expected to understand the full sequence and etiquette, a chaji is generally considered an advanced practice in the tea ceremony.