unsure of title

All I remember is a town was being tormented. One of the men went to learn kung fu and was told to build a wall around the training area. While doing so, he watched and imitated the training done. At the end of the time he came down and asked to learn kungfu and was told to take the wall down.
Minor fighting/chase scene and the main character ran out and back to town, where he never believed he learned kungfu.