Is it me, or did we just discussed Russia's WW2 tactics when the thread is about China's involvment in wars? There was a thread about this a long time ago, but I digress.
The last time China was ever invested heavily in war was the Korean War in the early 50's, in an effort to spread Communism to the Korean penisula, and likely to Japan. Long before that, they were a superpower in the ancient world that controlled much of what is now Mongolia, Indochina, Korea, even all the way towards Afghanistan and Russia. And as other people already mentioned, towards the 18th, 19th and 20th centuries is when China went to a superpower to being a British colony, and then a Japanese colony in the 30's and 40's.
Their million man army, and their nuclear arsenal may be considered a threat down the road for America and Europe, but with money flooding through to China now, I doubt they are in position do any damage to us or anyone else in the future.