According to the royal etiquette, the Chinese emperor should always consumes high quality food made of fresh ingredients daily, thus there are a lot of leftover vegetables in the palace kitchen.

[2] This stir-fried leftover vegetables of course, was not meant for the emperor or the royal family, but is served to feed the palace servants, eunuch and courtiers.

Cap cai was brought to Indonesia from the Fujian area, where the Hokkien people originated.

Subsequently, the Hokkien people are the dominant Chinese ethnic group in Indonesia.

This is also the reason why cap cai does not have a rigid recipe regarding the types of vegetables contained in it.