Tencent Holdings Ltd. and its partners will pay $8.6 billion for the Finnish maker of “Clash of Clans,” a deal that will catapult the Chinese internet company to the top of the white-hot market for games played on smartphones and tablets.

The deal for Supercell Oy, Tencent’s biggest-ever acquisition, reinforces the company’s position as the world’s biggest videogame publisher by revenue. It also highlights the Shenzhen-based company’s ambitions beyond China’s borders.

Tencent and its partners are buying an 84.3% stake in Supercell from Japan’s SoftBank Group Corp. and the startup’s current and former employees, the companies said Tuesday. The deal values closely held Supercell at $10.2 billion—nearly double its valuation a year ago.

Tencent is little known in the West, but the company’s market capitalization was about $207 billion based on Tuesday’s closing price, more than that of Oracle Corp. and Intel Corp.

Online games accounted for more than half of Tencent’s $15 billion in revenue last year. “We are very bullish on the [mobile games] market,” Tencent President Martin Lau said on a conference call.