According to Chen Kuan-Tai, most of the Shaw Brothers films took roughly two months to work on, but due to a tight schedule this had to be shot in one month. With this cramped schedule, director Cheh Chang was only able to direct during the night shoots, while uncredited director Hsueh-Li Pao directed during the day shoots.
Similar to when Bruce Lee starred in The Big Boss (1971), star Chen Kuan-Tai was a Cantonese speaker, but this film was a Mandarin production. However, unlike Lee, who spoke Cantonese during shooting and was dubbed in Mandarin later on, Chen actually learned how to say his lines in Mandarin, even though he wasn't completely sure what they meant. Ironically, Pei-Shan Chang was the Mandarin voice actor for both Lee and Chen.
The late Wo-fu Chen was actually in the running to get the role of Ma Yong Zhen, but lost out to Chen Kuan-Tai.
The symbol on the back of the cart that is unveiled midway through the film is the word "Ma", the main character's surname.