Li Zhibai contemplated the matter of the sword dance.
If Ms. Yun were to perform the sword dance, the primary concern would be physical stamina... However, there's no need to rush on the matter of stamina, as Yun Qian can start by training her posture, just like Ah Qing. Just by standing there, one can see that she is a girl with a solid foundation.
And training posture doesn't require much physical strength, so a girl as useless as Yun Qian can easily accomplish it.
As for the sword used for training... Unlike Chang'an who uses a standard longsword, women need to be nurtured with care. Besides, if she were to use an ordinary sword, Yun Qian might end up having half of her smooth black hair cut off before she even learns the sword dance.
