This year, China will surpass the U.S. as the largest smartphone market in the world. That's why the major tech players are all lustfully eyeing the region.

The latest partnership to be announced: Microsoft (NASDAQ:MSFT) is hooking up with China Unicom (NYSE:CHU), the second-largest wireless carrier in the world's most populous nation. China Unicom had 163 million subscribers at the end of October, including 70 million 3G subscribers.

According to China Daily, the alliance is expected to help boost Windows Phone's market share in the Chinese market, which currently sits at less than 3%. Investors may remember that China Unicom was Apple's (NASDAQ:AAPL) first Chinese carrier partner to launch the iPhone along with its 3G network back in 2009, so Microsoft is butting in on one of Apple's iPhone carriers.

Microsoft COO Kevin Turner added, "China is the No. 1 market worldwide in terms of PC, tablet, mobile and Internet users. It is a very exciting place."

Much like in the U.S., Chinese carriers have an incentive to diversify their platform base, and Windows Phone is becoming a viable alternative. China Unicom general manager Lu Yimin said the carrier would help promote Microsoft's platform.

This official pairing comes just days after HTC launched its Windows Phone 8X and 8S on all three major Chinese carriers. Microsoft's main mobile hardware partner Nokia (NYSE:NOK) also announced that it was launching a version of its new flagship Lumia on China Mobile's (NYSE:CHL) network this month -- a much larger subscriber opportunity for Microkia, with over four times as many total subscribers (but only 9 million more 3G subscribers).

Nokia CEO Stephen Elop recently said that China was the biggest market for his company's Lumia lineup, but didn't provide any unit sales data. For reference, Nokia sold 2.9 million Lumia devices last quarter, which was 46% of its overall smartphone shipments.

With Windows Phone devices now available on all three major carriers, some market share gains may be in order.

Fool contributor Evan Niu, CFA, owns shares of Apple. The Motley Fool owns shares of Apple, China Mobile, and Microsoft. Motley Fool newsletter services recommend Apple and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.