In Asia, the largest law firms are getting even larger. Thanks to global mergers and local market consolidation, the gap between bigger and smaller law firms in Asia last year widened by 13.6% from a year earlier. It is almost 400% larger than it was six years ago, the first year we collected data for our annual Asia 50 lawyer headcount survey.

Unsurprisingly, leading our list of largest Asian firms is global giant Dentons, with a worldwide head count of 7,445, up 13.5% year-on-year. Six years ago Dentons, then Dacheng Law Offices, also led our very first Asia 50 list, but with only 2,027 lawyers.

Meanwhile, the smallest firm of today's Asia 50, India's Luthra & Luthra Law Offices, had 301 lawyers, 19 more than the headcount at last year's number 50, China's East & Concord Partners.

In 2016, 10 Asian-based firms had more than 1,000 lawyers globally, with all but one of them based in China. Chinese firms now occupy half of the Asia 50. Through domestic and overseas expansion, Beijing DHH Law Firm saw the largest year-on-year growth on our list, 82%, and reached 1,035 in global headcount.

To compile our rankings, we rely on three sources of data. For the Asia 50, we survey firms based in the Asia-Pacific region. We also rank the non-Asian firms with the largest headcounts in Asia, drawing on information from the NLJ 500 survey of US firms and on data gathered by Legal Week. We categorise a firm's nationality based on the market where it has the most lawyers. All lawyer numbers are full-time equivalents (FTEs) for the previous year, 2016. Under this methodology, Ashurst, despite its UK legacy, is considered an Australian firm and is thus ranked on the Asia 50, while Herbert Smith Freehills (HSF), although prominent in Australia, is treated as a British firm.

Dropping off the list were two American firms, Winston & Strawn, which closed its Beijing and Taipei offices in late 2016, and Weil Gotshal & Manges. Winston & Strawn said closing in Beijing and Taipei was aimed at focusing its Asia practice more efficiently in Hong Kong and Shanghai. Orrick Herrington & Sutcliffe also reorganised its China practice, a move that resulted in nine partners leaving for Morgan Lewis & Bockius in early 2017.

But as the widening gap indicates, when some scale back, others stay put. Baker McKenzie Asia-Pacific chair Gary Seib says the firm has continued its commitment to the region by adding locally based lawyers: 110 so far in 2017. Morgan Lewis, after taking the nine-partner team from Orrick for a Hong Kong office launch, also expanded in Shanghai with a five-lawyer employment law group.

"If you have a strong and integrated global platform," firm chair Jami McKeon said earlier this year. "I'm convinced size is an absolute advantage."