The "best translation" turns out to be the idiomatic translation.... which refers to the windings of a silk worm as it lays out the cocoon. Probably the best translation is still going to be vague and not very explicative: chansi gung would be "winding exercises".
Right, you twister. That's why "CHINESE" sources have been saying "reeling silk" for decades when they were using English. That's why they all describe pulling
the silk from
the coccoon: they are referring to the worm putting the silk on
the coccoon. It makes sense...in Sigmanland.
to bother; wind around; wrap round; coil; involve; annoy; tangle
Silk, thread, trace
The detailed description of the effort always refers to drawing the silk from the coccoon and onto a "reel."
So yes, "they" do "call it reeling silk" when they're speaking English, and their illustrations prove that they're not talking about the worm, you silk producing fellow.