So Tak Chung, 59, remembers how different things were. When he was a boy, he and his friends would run home from school as fast as they could to watch kung fu shows on television.

“Kung fu always gave me a sense of justice and pride in being Chinese,” Mr. So said while stretching his legs for a Sunday night lesson at Kowloon Park. “It feels like if you knew kung fu, you could beat the bad guys and help the needy.”

Mr. So’s master, Mak Che Kong, 64, is less hopeful about the future. He ran one of the last studios in Kowloon in the 1980s, but soaring rents caused it to shut down, along with other family businesses that were once a fixture of Hong Kong street life, like Dit Da, or bone-setting, shops that use traditional Chinese medicine to treat sprains and fractures.

Mr. Mak, who is not related to the author of the martial arts history, has fewer than 20 students now, down from twice that number several years ago. Most students are over the age of 40.

He holds classes all over the city because “students will not come if they need to travel much.” On Tuesdays, he teaches at a pier in the city’s Central District; on Wednesdays, near a government marriage registry in Sha Tin in the New Territories; and on Sundays, at a public park in Kowloon. On Mondays and Fridays, he teaches at a kung fu school in a warehouse opened by one of his students.

Describing himself as “old school,” Mr. Mak fiercely defended kung fu traditions. “Chinese kung fu is not about fighting; it is about patience and hard work,” he said.