Location: Shaolin Temple
Prerequisite: Complete Hui Da the Strange Monk I, Affinity 20+
Petitioner: Hui Da
Reward: Black Jade Chant
In order to trigger this quest you need to complete Hui D the Strange Monk I. Once that's done, raise your Affinity with Hui Da to 20 or more to trigger the second part of the quest. The quest won't appear immediately after raising your Affinity with Hui Da, so save your game and reload it. He should be ready to offer the quest.
Hui Da is still enjoying the flute you got him during the first quest. He would, however, like an additional instrument: A Spring Thunder Guqin. The only clue you get is that someone in Yanfu Town has one of these guqins. You'll find Yanfu Town to the southwest of Shaolin Temple.
Check inside the inn, on the east side of Yanfu Town. There are two people sitting on the right side of the inn, and the lady, Guo Rong, has a Spring Thunder Guqin in her inventory. You'll need to raise her Affinity to 20 (she likes flowers and coins), then Spar with her and defeat her until she drops the Spring Thunder Guqin. Guo Rong is not a weakling, so don't expect to be able to take her down right at the beginning of the game.
Take the Spring Thunder Guqin to Hui Da to earn your reward. After this you can continue to push your Affinity with Hui Da, and if you reach 60 you'll unlock another quest.