The wabi of onjaku (warm stone), kaiseki, and ichiju-sansai

At a tea ceremony, a simple meal is served before tea. This was previously referred to as furumai, kaishoku, or kaiseki. Retaining the same pronunciation of kaiseki (party seating), the word later came to be spelled using characters that mean “bosom stone” derived from the zen concept of onjaku, referring to the warm stones that monks would hold against their chests for comfort against cold weather. Therefore, kaiseki in no way refers to gorgeous course meals in high-class restaurants. Moreover, it is not necessarily synonymous with Japanese cuisine. Its origins can be traced back to Buddhist vegetarian dishes from southern China, and the word means a meal sufficient to temporarily tide over hunger for just as long as the warm stone remains warm.
Suimono (clear broth soup), kuzukiri (kudzu starch noodles), and somen (vermicelli) were all foods that emerged with tea ceremony kaiseki. The cuisine underwent further culinary refinement during the Edo period, eventually resulting in the rule of ichijusansai (one soup and three side dishes).