Episode 172

With Tetsusaiga's new power, Toto-sai sends InuYasha to a demon hermit named Yorei-Taisei to train so he can use it without it backfiring. When InuYasha reaches the village, he undergoes a test by the hermit designed to help InuYasha discover the existence of whirlpools of demonic energy that InuYasha can cut to defeat his enemies. Meanwhile, Moryomaru devours two demon twins and obtains their abilities.