Yu's career began to blossom when at age 16, already a veteran performer, he went to Taiwan to perform Peking opera in the Japanese occupied nation. "Before I went there, the Taiwanese had little chance of seeing Peking opera," Yu says. When Yu returned to Shanghai two years after he was invited to join the Peking opera troupe, which performed regularly in the famous Big Theatre. At the same time, Yu was awarded the prestigious position of martial arts director, not only for the Big Theatre, but for the other Shanghai theaters as well. Yu attributes this honor, unusual for someone so young to his special talents: his tall skinny figure gave him a more prepossessing state presence than his rivals and his somersaults were better than the others. "I also had a good voice," Yu adds. Since performers of military roles are not expected to sing well, this gave him a decided advantage. Yu was to keep this position for 20 years.
The martial arts director had a weighty responsibility. "If a new play were being performed, I would design the costumes. Peking opera has strict rules for costumes. One must go with the rules, but then you can add your ideas. "I would also direct the special fighting sequences, and invent them for new players." Any decisions Yu made about new sequences would be continued, immortalized, for as long as that play would be performed.