Pilgrim saw the eldest working a brow-high staff, hopping about with it, and took the gold-banded rod out of his ear. He gave it a shake and it was as thick as a bowl and something over twelve chǐ long.

Here is the answer to the weapons the princes carried out of the palace, and it comes at once: the eldest is using a staff, so Pilgrim produces a staff. 跳阿跳的, hopping and hopping, is faintly unkind — the boy is bouncing about with his stick. 長 is cháng here, length, not the zhǎng of an elder. A chǐ was about 32 centimetres in the Ming, so a rod of 丈二三 stands roughly four metres tall, and it came out of an ear.

He drove it once into the ground, sank it some three chǐ deep, and left it standing there.

著 is zhuó here, the sense of making contact with something — driving it against the ground — rather than the zhe that marks an action going on. Three chǐ is a little under a metre. Nobody is threatened and nothing is struck; he simply plants it in the courtyard and steps back, which is a far better piece of theatre than a blow would have been.