Kayaku-don” refers to udon noodles with as many as nine different ingredients, including shiitake mushrooms, fish cakes, bamboo shoots, komatsuna (Japanese mustard spinach), chicken, and green onions. The name “kayaku” comes from the nutrients in the ingredients such as shiitake mushrooms and eggs, which are regarded as “medicine” and added to the dish. Some believe that the word “kayaku” became “kayaku = added medicine.
The origin of kayaku udon can be traced back to “shiboku udon,” a local dish in Kagawa Prefecture, in which several ingredients such as radish, carrots, and chicken are stewed and poured over udon noodles. When this dish was introduced to the Kansai region, it came to be known as kayaku udon. In fact, people in the Kanto region have rarely heard of kayaku udon, while those in the Kansai region know it well.
When it was introduced to the Kanto region, it is believed that the names “Gomoku Udon” and “Okame Udon” were used. It also seems that various names exist depending on the region.
According to Professor Shinzawa of Hokuriku Gakuin University, the word “kayaku” refers to ingredients other than meat, and it has been called “kayaku” for ingredients other than meat in sukiyaki and other dishes since the Muromachi period.
