Book 2, Chapter 5 - The Father of Spring Grass

The time passed, day after day. The days slowly grew colder, but his father still had not returned. The Ji clan of West Prefecture had long since sent a squad of black armored riders to surround Serpentwing Lake. Within the training yard. One sword attack after another howled and flashed through the air. Ning stood there by himself, training in the [Raindrop Sutra]. At this point, neither black armored riders nor powerful monstrous beasts…were of any use to Ning in terms of improving his swordplay....