Peas yellow is a traditional Beijing snack. According to Beijing custom, pea yellow is eaten on the third day of the third month of the lunar calendar. Therefore, whenever spring pea yellow is on the market, it is supplied until the end of spring. Beijing's pea butter is divided into two kinds: palace and folk. The best peas are flower peas from Zhangjiakou. Pea yellow is a traditional Beijing snack, with the kidney bean rolls together into the Qing Dynasty Palace.