kaiseki tea ceremony
In the CHAJI (茶事) or formal tea gathering, the meal served to customers is called KAISEKI (懐石). This is the word of Zen Buddhism that is closely related to the establishment of the tea ceremony. It is said that Zen Buddhist priests ate only a small amount of food so that various hesitations would not come to their minds when they practiced meditation.
As it gets colder in winter, the monks bake stones which were called ONJYAKU or ONJAKU (温石) and wrap them in cloth, putting them under their clothes to keep out the cold.
The word for Kaiseki (懐石) was said to have come from this, sharing the same last character "石". Another story said that a small stone, the onjaku was given to a visitor to give relief from the hunger while waiting. This eventually became the light meals observed today as the kaiseki.
Before Rikyu/利休 started to have tea gatherings, the invited guests put something like a lunch box called WARIGO/破子 in their bosom pockets, and each brought food, so it was called "KAISEKI (懐石)". But after Rikyu has started to have tea gatherings, it changed to a style of serving meals to the invited guests.
KAISEKI (懐石) is prepared by the TEISHU(亭主) or owner, who searches for the ingredients himself, cooks with his own hands, and serves them to customers. Therefore, it is not a special dish, but a dish that is deeply considerate of the owner for the guests.
KAISEKI (懐石) for the SHOGO NO CHAJI (正午の茶事) or noon tea gathering is a formal meal, so it is accompanied by alcohol. Especially when you have HASSUN (八寸) or second course, the owner and the guest exchange a sake cup called SAKADUKI and enjoy the time of the once-in-a-lifetime oppotunity 一期一会.

The basic flow of KAISEKI (懐石) dishes in the formal tea gathering is first of all, soup, rice, and MUKOUDUKE (向付) which is a dish of seasonal food such as raw fish are served in a large square tray called OSHIKI (折敷). This is followed by simmered food called NIMONOWAN (煮物椀) and grilled food called YAKIMONO (焼物).
Collectively the meal is known as “one soup and three dishes" or "ICHIJUSANSAI" (一汁三菜 ) and this style has come to form the base of the current Japanese menu.