Tenderpaw By Name, Tender Paw By Reputation

I'd like to go tell Xiao, Kang, and the others that I've found the hidden master, but now he won't let me leave! He says I have to pass that test of bamboo first. <Lin whispers:> How'd you do that, by the way? It looks like, for the time being, I'm stuck here practicing my punches against this rock. And my knuckles are about to cave in. If you could gather some jademoon leaves, I could prepare an ointment and at least numb some of this pain.