Well, it's hard to say for sure without knowing which specific manga you're referring to. Sometimes she might play a flute, or maybe a piano. The possibilities vary a lot depending on the story and the author's imagination.
Chapter 650, "Trouble on the Island?", is the clearest early answer because it turns Shang Shuyue's situation into a concrete plot event. The chapter gives readers a real answer by opening on Pei Ye instinctively shielded everyone behind him.
Chapter 842, "Uncle Zhao?!", is the clearest early answer because it turns Uncle Zhao's situation into a concrete plot event. A useful checkpoint is the way the scene starts with But revealing is one thing, not making the old lady and the old man...
Chapter 641, "Congratulations to Jiang Li for Taking the Top Spot!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Surrounded by a sea of fire.
Chapter 656, "If he's the grandson of the richest man, then I am the richest man!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 638, "The person was really eliminated by me!", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Outside the wooden hut, several people were startled after a message...
Chapter 857, "Interested in joining us?", is the clearest early answer because it turns Fuhu Mountain's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Jiang Li looked at his face, which was black-purple, black-purple,...
Chapter 718, "This Person Is No Longer the Same Person", is the clearest early answer because it turns Miss Jiang's situation into a concrete plot event.
The best chapter pointer here is Chapter 25, "He's Actually Mr. Shen's Son?!". It opens with Therefore, from his childhood, Jiang Shixu had felt an extreme aversion to... and closes on Having worked beside Shen Lan for over a decade, she had been there when....
Chapter 877, "You Are Not the Real Jiang Li!", is the clearest early answer because it turns Weibo's situation into a concrete plot event. It opens with The Gu Family values their reputation greatly and has a dedicated PR...
Look to Chapter 16 for the clearest answer. It begins with Just as the words fell, Jiang Shixu swiftly cast his eyes downward., keeps building through His eyelashes were very long;