During the day, woe betide any stranger who tries to make it through the front gates of the military compound. But after 8pm at night, behind the large entrance placard reading "Serve the People", the locals loosen up a bit and the doors are thrown wide to the "Hot Spot" disco, situated in the heart of the factory complex. The music may not veer very far from the mainstream, but it must be the most secure late night joint in town.
Guo Xiaobo, the 30-year-old general manager, is slightly reticent about the technical input of the PLA to the laser beam display above the now flamboyant entrance to the compound. How Mr Guo came to establish Peking's latest disco in the middle of a military factory is another state secret. "When I was young I used to play the horn in this building," he explained.
There are times in China when one should not ask the obvious questions, and this was one of them. It seemed better to let Mr Guo do the talking.
The disco opened two months ago, owned by Mr Guo and two unidentified business partners. But as far as the Public Security Bureau is concerned, it is run by 3501 factory, he said, because these days only state-owned enterprises are supposed to be opening discos in China. In reality he has managed to do a deal whereby he simply pays the factory an annual rent of 1.6m yuan (pounds 128,000). And why did the factory agree to rent the building? "To earn money," he said. "In the past it was a cinema here, but there were not many people in the audience."
Mr Guo, who made his money in real estate down on China's southern Hainan island, said he had "quite a good relationship" with the 3501 factory as a result of previous business dealings, but preferred not to elaborate. What did the factory actually manufacture? "That's secret," he said.
There were benefits to such an arrangement for a disco, he added. "The location is good, tax is only half because it is a military factory, and it is the safest place." So what were the drawbacks? "The formalities are quite complicated. And if there are any problems in the future and I end up in court against the military factory, I will never win."
On a sultry Friday night, the military still has a role to play. Mr Guo has employed a dozen demobilised soldiers to man the doors. Once inside, and through the metallic tunnel which takes one to the main arena, the spirit of the Eighth Route Army is overwhelmed by the total disco experience that Mr Guo and his colleagues have created at a cost of 28m yuan (pounds 2.2m).
According to Mr Guo, this is the only venue deemed by the Peking Cultural Bureau to be a "Special First Class Disco". Onan average night about 1,000 Pekingers pay up to pounds 4 to share the excitement.
State-of-the-art lighting equipment is matched by a hydraulically-lifted DJ podium. But the disco business in Peking is very competitive these days. So the special feature which Hot Spot offers is a pair of elevated cages, big enough for two, and reserved for what Mr Guo calls "sexy dancing".
He added: "The day before yesterday, two foreign women danced there, it was quite a good result."
Sadly, the night I was there, by 11.30pm the dancing was still not raunchy enough for the DJ to open the cage doors.