KEY POINTS:
In the hills around Beijing, an army waits. Armed with 37mm anti-aircraft guns they wait not for aircraft nor invaders. The enemy is clouds.
They are clouds carrying rain. Beijing did not want rain to spoil the opening ceremony nor other key events of the Olympics. So they shoot the clouds.
Not with artillery shells, mind. With chemicals, designed to get the clouds to drop their rain before they hit the Olympic venues, or to remain dry and pass harmlessly overhead.
Yes, China even tries to control the weather and, even though there is some scepticism about success rates, they have made a whole industry out of it, involving volunteer gunners and 40-year-old anti-aircraft artillery.
Herald on Sunday efforts to visit one of the cloud-shooting facilities were denied, but a lot is known about the Chinese programme run by the wonderfully named Weather Modification Division of the Beijing Meteorological Bureau.
The authorities allowed the name of one of the gunners to be published (but not photographed) - Zhang Geng, a 40-year-old farmer from the village of Beixing in the Fragrant Hills.
He waits for his phone to ring with news from the bureau that likely looking clouds are on the way.
Then he meets seven other members of the shooting team at his gun. Four carry the shells and rockets to the guns, two load and two fire.
They are not alone and, like everything else in China, the numbers are staggering.
Over the past five years, China has spent about $700 million on shooting clouds. With good reason.
Depending on the chemical contents of the shells Zhang and other gunners fire into the clouds, they either produce rain or persuade the clouds to retain their loads. China needs water, and lack of it can hamper economic growth.
Over the five years from 2000-05, according to state news agency Xinhua, shooting the clouds has produced 275 billion cubic yards of water - enough to fill China's huge Yellow River twice over.
So there is ample economic incentive for the cloud-shooting programme, even before factoring in the country's image as it desperately tries to show its best face during these Olympics.
There are up to 50,000 people employed in the rainmaking and rain-stopping programmes across China, and 6500 gun emplacements and 4000 rocket launchers are used nationally.
They have been successful too - China claims that rainfall has increased across the country by 10-25 per cent because of the programme.
But there is a drawback to the rain game.
Rainfall helps to clear the eye-smarting smog which blankets the city from time to time, so measures which are aimed at preventing rainfall may not help clear the airborne fug.
Beijing has spent an astonishing $20 billion to beautify the city and clear the air but the smog remains persistent - in spite of the government English language newspaper China Daily carrying a dubious story that the city's air does not pose any health risk for athletes.
China may yet introduce further emergency measures to cut air pollution during the three weeks of the Games, including taking 90 per cent of Beijing's cars off the streets at peak times, and closing more factories and building sites.
Maybe, too, people like Zhang Geng will be asked to train their guns skyward and shoot the clouds to make rain, helping to clear the smog.
