However, the Jin returned soon after with enough siege machinery to scale Kaifeng's layer of walls defended by 48,000 Song troops.

Catapults and siege machinery flashed into charred heaps, while kettles of oil exploded into gigantic fireballs.

In such a case, a sally might drive back the attackers, destroy the siege machinery... but it wouldn't change the inevitable outcome.

Trenching and revetments had been dug and built such that getting siege machinery like a ram close enough would be a slow and deadly process.

Though the fortress itself was not large, the steep slope upon which it rested made bringing siege machinery against it all but impossible.

And all around it there appear to be campfires, and what look like tents, sentries, siege machinery, and so forth.

"I wish we had some of the siege machinery the Romans know how to build," he said wistfully.

Then the creak of ancient siege machinery.

No siege machinery could get close, and a catapult would have to operate from the valley below.

It would need siege machinery such as would take weeks to assemble.