Training the Technique of Interchangeability

Ye Mo was slightly perplexed. What was the point of buying 10 throwing knives?

"If I tell you to buy it, do it. If not for insufficient league points, I would have told you to buy 20. Come on, pick 10 throwing knives, the smaller, the better."

The throwing knives on the walls came in different shapes and sizes. Ye Mo followed Ling'er's instructions, picking out 10 of the smallest knives before leaving the hall. 

With another 5000 league points deducted from his mission card, Ye Mo was now left with 2000 league points. 

In the woods of the Outer League Spirit Mountain, there was an empty area with no one around. Ye Mo took plenty of effort in finding this place. 

"Ling'er, what is the point of these 10 throwing knives?" 

"The Technique of Interchangeability is strong because of the element of change. The technique that you displayed before only took slight advantage of speed, but not change."