In hypermodern Hong Kong, a debate over 17th-century fashion is dividing the city's legal circles.

The city's lawyers are among the last in the world to wear judicial wigs, those curly, horsehair headpieces that are a legacy of more than 150 years of British colonial rule. The affection is so great that one group of lawyers that doesn't wear wigs wants the right to don them. The city's wig-wearers are resisting.

The feud has ignited passions over the wigs. "When I wear my wig, I know something big is going to happen," said Jacky Lai, a Hong Kong lawyer. "It makes me feel like I have more responsibility. I think I exude more energy than without it. It's magical."

Others say the wigs, and the robes that go with them, are anachronistic or ill-suited to Hong Kong's subtropical climate. The city's courtrooms are heavily air-conditioned, partly to keep lawyers cool, says lawyer Kevin Tang. "People complain, but it's because all the counsel are dressed up—they have to make sure they don't faint."

The split over wigs mirrors the divide in Hong Kong's legal profession. As in the U.K. and some former British colonies, Hong Kong's lawyers are split between solicitors, who work directly with clients, and barristers, who represent those clients in court. The difference has historically been easy to spot: Barristers, like judges, work in an elaborate uniform of robes topped with hand-woven hairpieces.