In the Sui dynasty (581–618), the suburb of Huiluo was half a mile north of the Luoyang city walls, where the Sui’s founder ordered his subjects to sink a granary pit, nine metres deep, sufficient to hold half a tonne of grain. Over the next nine months, workers dug 300 of them across an area that today spans several city blocks, storing wheat, millet and beans for the people. It was an incredible achievement in engineering, a real example of the kind of long-term planning that should have allowed the Sui to endure for generations…. except, as you might have noticed, the granaries were outside the city walls, and reflected an unwarranted confidence that there would be no civil unrest.

In the civil war that toppled the Sui, a rebel general realised that he had no need to attack Luoyang. He could simply seize its massive food supply and wait for the starving city to surrender. As the Tang dynasty shifted back to a new capital in Xi’an, the strategically vulnerable Huiluo granary pits, each of them the size of a house, were abandoned.

Wang Ju, the affable chief archaeologist at Huiluo, shows me where silt and sediment washed in over the years that followed. The roofs collapsed, and at some point in the next few centuries people forgot they were there. He and his associates excavated five or six of the granary pits, and turned the area around several dozen others into parkland, with the location of each granary marked by a little round hedge. But a few years ago, work stopped, and the exhibition hall at the site remains closed to visitors. It is difficult, in an age of Terracotta Warriors and over-the-top reconstructions of ancient carnivals, to get tourists all that interested in a bunch of holes in the ground.

We climb down the crumbling earth steps into the bottom of one of the pits for him to show me layers of sediment and the traces of the old granary lining, which is where I noticed a manhole-sized circle of discoloured earth.

“Oh, that,” he laughs. “That’s where the tomb raiders tried to get in.”

They used a Luoyang shovel, a semi-circular trowel on the end of a long pole, pushed into the earth to take core samples. Push one into the ground anywhere around Luoyang, and you may luck into an old grave or buried temple. The poor chancers in Huiluo found what they thought was the side of a tomb, and wasted a night or two digging down to find nothing but an empty pit.

“And the thing is,” says Wang, “they didn’t do it that long ago. You can see where the earth is different in the tunnel. Rain washed sediment in, but it did it much more recently, maybe only thirty years ago. So they were probably digging their way in around 1970 or 1980. These tomb raiders, they’re kids. They’re always young and stupid, like 19 or 20, and think they are on to a good thing that’s going to make them rich. They can dig down nine metres in just three or four hours, working by hand, in shifts. And we’re archaeologists, we can get forensic on them very quickly – we can dig out the tunnel and work out who they are from what they leave behind – cigarette packets or particular beer cans.

“And they didn’t find anything because there’s nothing here, which is probably why we never got any funding to open the others, and why we still haven’t opened this museum, five years after it was built. Nobody wants to come and look at empty pits.

“It was worse in the old times. You wouldn’t believe the stuff we’ve dug up elsewhere. There was a tomb in Xi’an where they found a tomb robber crushed under a stone near the head of the tunnel. I reckon they brought in a new guy, found something really valuable, and killed him on the way out so there was more to go around. I mean, we’re talking about grave-robbers here. They’re hardly stand-up people.”

I find myself thinking that Wang might have more luck with his exhibit if he made more of the people who tried to rob it. There are a lot of tomb raider stories about, particularly in Xi’an and Luoyang, both of which functioned as capitals during the Tang dynasty (618–907), the pinnacle of China’s high middle ages, when, for a time at least, the nation was rich, the people were happy, and the culture was suffused with innovations and ideas from along the Silk Road.

Jonathan Clements is the author of The Emperor’s Feast: A History of China in Twelve Meals. These events featured in Route Awakening S05E01 (2019).