Ugly orange, whose scientific name is "I don't know fire", tastes sweet and has a thick and big skin. There is a skin tumor on the stem. Originally from Japan, it was introduced to Dan Ling, Sichuan in 2005. Because of its ugliness, it is also called "ugly orange", "ugly orange" and "ugly monster" near Chengdu. The main producing areas are Dan Ling, Pujiang and Jintang in Sichuan, and Neijiang, Chongqing, Yunnan, Jiangxi, Hunan and Zhejiang in Sichuan. There are also local cultures in other places.
Ugly orange was bred by crossing 1972 nakano No.3 ponkan in kurume Branch of Horticultural Experimental Field of Japanese Ministry of Agriculture and Water Resources. Because of its excellent flavor and excellent quality, it is the most expensive citrus variety in Japan in recent years.