Images - the image of the emperor should probably have it's PD-art tag on Commons fixed, but it's not required for GA status.
"effectively capturing Dou Jiande"? I'm not sure what this is supposed to mean... was he captured or not?
"began to breed unrest in the provinces" - a bit colorful for an encyclopedia article - could we go with something a bit less colloquial?
You say "during the later reign" of Yang ... but when were the years he reigned?
"others contending themselves, for the time being, with more modest titles" I think you mean "contenting"?
"the Tang, led by" ... "the Tang" or just plain "Tang" as you do in the lead?
"Zheng dynasty" do we have a link for this?
The redlinked (I assume piped) "defeated" is really jarring - suggest if you're redlinking a battle or similar, you drop the piping.
Li Shimin's campaign:
"establish a leaguer of fortified camps" - suggest a different word than "leaguer" - it's a pretty rare word.
"for rescue was an intervention of Dou Jiande" - awkward - suggest "for rescue was an intervention by Dou Jiande"
"It was not therefore probably by design that Dou waited until April, when Wang's situation was critical, before he began marching west to relieve the siege of Luoyang." Do you mean "It was probably not by design that Dou waited until April, when Wang's situation was critical, before he began marching west to relieve the siege of Luoyang." or "Therefore, it was probably by design that Dou waited until April, when Wang's situation was critical, before he began marching west to relieve the siege of Luoyang."?
"some 60 miles to the east" - needs conversion to metric as well as the imperial units given.
"a plain ten miles east" - as above, needs conversion.
Link for "Huanyuan Pass"?
"The plan was supported by Dou's wife, but was not adopted due to the vehement opposition of the Xia generals, who dismissed Ling Jing as an armchair general, and some of whom had allegedly been bribed by Wang Shichong's agents." Suggest turning that last phrase into a standalone sentence - it's a bit of a convoluted sentence as it stands.
"Li Shimin's plan was crowned with success.." again, a bit unencyclopedic. Suggest "Li Shimin's plan was successful..."
Link for "Mandate of Heaven"?
Are there any monuments/commemorations on the site of the battle today?
I've put the article on hold for seven days to allow folks to address the issues I've brought up. Feel free to contact me on my talk page, or here with any concerns, and let me know one of those places when the issues have been addressed. If I may suggest that you strike out, check mark, or otherwise mark the items I've detailed, that will make it possible for me to see what's been addressed, and you can keep track of what's been done and what still needs to be worked on. Ealdgyth - Talk 18:59, 26 July 2013 (UTC)
Thanks for taking the time for this review. I've fixed most of the points you raised, as well as rewriting the lede a bit. On the link for the Zheng dynasty, it is not recognized as a formal dynasty and was essentially a non-starter since Wang Sichong was defeated. On modern monuments, I haven't been able to find anything so far. I'll certainly add it when and if I do so. Cheers, Constantine✍ 10:03, 29 July 2013 (UTC)
Looks good to me, passing now. (Sorry for the delay, life's been a bit busy! ) Ealdgyth - Talk 20:24, 31 July 2013 (UTC)