Interconnected-arm gibbon

According to Robert van Gulik, this myth "must have been caused by the truly incredible speed with which a gibbon reaches out with one arm while keeping the other close to its body.

However, this interpretation is controversial, as Beng, Ba, Ma, and Liu—who lose basically every battle without the Monkey King—are too incompetent to be rated so highly by the Buddha.

One day, overcome by curiosity, he opens a secret box and brings Heaven's Teachings to earth, leading to a series of disasters that culminate in Wang Ze's rebellion in the 1040s.

Eventually Yuan Gong redeems himself and for his role in quashing the revolt, he is restored to his former position of Lord of White Cloud Cave (白雲洞君).

[1] Many human characters from subsequent novels have also been given this nickname, including: Han Tong is even said to be the founder of tongbiquan ("interconnected-arm boxing"), or tongbeiquan, a school of Chinese martial arts.

"Gibbons at Play" ( 戲猿圖 ), a 1427 painting by the Xuande Emperor , now in the collection of the National Palace Museum .
"Oak Leaves and Two Gibbons" ( 槲葉雙猿圖 ), an 11th-century painting by Yi Yuanji .