《史记·三十世家·孔子世家》
过了些时候，师襄子又说： 你已熟习弹琴的技法了，可以学些新曲子了。 
有间，曰： 已习其数，可以益矣。 
After a while, Shi Xiang Zi said again, "You have become familiar with the techniques of playing the qin, you can learn a new song now."