Before Brian Eno spotted what an excellent title it has, this was best known as one of the Eight Model Operas approved for performance during the Great Proletarian Cultural Revolution (not a lot else got on stage in those days). A Peking Opera to be precise, though apparently they were translated into other regional Chinese opera styles. In those days Jiang Qing, then wife of Mao Zedong, took a personal hand in China's performing arts - she came to Shanghai to do the final revisions for a performance of the piece herself in 1965 (the eve of the Cultural Revolution or 'decade of chaos' as it's now sometimes called in China). According to the reminiscences of one of the performers at time, she 'encouraged us to display the tenacity of revolution, to constantly polish and improve our performance, and thus make this opera a revolutionary model' (鼓励我们要发扬革命的牛劲，精益求精，把这出戏搞成革命的样板)(1).
The original Chinese name is 智取威虎山 (zhi qu wei hu shan) - it was written in 1958, an adaptation from the novel 林海雪原 (Lin hai xue yuan - 'Boundless Forests of the Snowy Plateau') by Qu Bo. It tells the story of a 1946 attack on a Guomindang 'bandit' camp on Weihu Mountain (in present day Inner Mongolia) by the People's Liberation Army. A soldier Yang Zirong (杨子荣) disguises himself as a bandit and tricks his way into their camp claiming to have a map of PLA troop placements. Yang inveigles his way into the trust of the bandit leader, all the time sending spy reports on how to take the well defended mountain stronghold to his comrades below. Just as the PLA are preparing to attack, Yang is nearly exposed by the return of an escaped bandit prisoner who knows his true identity. He buys time with a vigorous denial of the returnee's allegations, working his way close enough to shoot the bandit leader. Just in the nick of time the militia and army arrive to save the day.
It was still packing 'em in Shanxi in August of this year (in a slightly updated version) according to the story referenced below (2). I've not seen it myself, but the critical reviews are uniformly good (even now they don't have to be), praising its strong story line, top tunes and vivid characterisation.
1. http://www.lmstamp.com/I/036.htm
2. http://www.daynews.com.cn/mag2/20020827/ca74213.htm
You can hear an aria from it here: http://library.kcc.hawaii.edu/~bzhang/pkopera/pkopera.html
Some background on the Model Operas and their continuing appeal can be read here (in English): http://app1.chinadaily.com.cn/star/2002/1107/cu18-1.html