TL;DR: you may not be able to find a direct flight to wherever you're trying to go in China, but if you're flexible with your gateway and connecting cities, West Coast transpacific availability is wide open right now. Because my travel interests skew toward European destinations, most of the coverage of airlines and availability on this blog has been focused on transatlantic awards. (Also, living on the West Coast means that transatlantic business class awards usually offer really good value, especially if you break it down to miles required vs flight time.) However, I was thinking in general about reasons I might need to be in Asia, such as scratching Angkor Wat off of my bucket list or visiting vendors in Shenzhen for work.
With that in mind, I did some lookin' on Delta and United - which I suppose is limiting, given that I didn't even consider OneWorld, but there you go. Plus, I know you can only stomach so many screenshots of availability calendars.
Now, I realize Asia is a very vast place, but if you're flexible, there's pretty great West Coast - China availability right now (and you can connect onto Siem Reap if you want to make me jealous with your selfies in front of Angkor Wat). Depending on which miles you have, your gateway cities/connections will be different, but you definitely have options. Let's start with Delta, who has business class level-1 availability between LAX and Guangzhou or Shanghai every goddamn day. From there, adding connections to Siem Reap or Hong Kong (the two destinations I'm most likely to have, because don't forget this is all about me) doesn't affect the price or availability.
Okay, SkyTeam is covered. Between China Eastern and China Southern, you should have no trouble crossing the Pacific in a flat bed. What about Star Alliance? If you don't mind connecting through Seoul, you're all set on Asiana. Here's SFO-ICN for April and May. Bountiful!
What if SFO and LAX aren't convenient for you? Maybe you live in the lush Pacific Northwest and would like to fly to Shanghai... Well, don't worry - China Eastern has your back. Here's the calendar for VAN-PVG, non-stop only.
Maybe it's common knowledge that there's a shitload of availability from the West Coast to Asia, but I seriously feel like people are going to accuse me of Photoshopping those screen shots. EVERY DAY? Dang. I even started looking at specific Delta flights, like SEA-HKG, although availability isn't as reliable as it is on partners. However, if you look out into June/July, there are usually a couple days a week where SEA-HKG is available too. (I'd argue that VAN and SEA count as the same area, given that it probably takes less time to drive between them than SFO and Oakland in traffic.)