Demon Slayer: Kimetsu no Yaiba Hashira Training Arc Episode 4 English Dubbed Episode Title: To Bring a Smile to One's Face Episode Description: In Muichiro's stage, rapid movement, Tanjiro witnesses the Hashira's strict attitude as he instructs and spars with the trainees, emphasizing perseverance even when injured. Muichiro, while acknowledging his harshness, intends for them to learn that even one mistake could be fatal in battle. Later, he spars with Sanemi and Obanai, who have taken up nightly combat training to improve their skills. Muichiro is impressed with Tanjiro's quick learning and ability to spar with him, allowing him to proceed to the next stage. Before doing so, Tanjiro challenges him to a paper plane contest, under the condition that he treats the trainees better if he wins. Though Tanjiro loses, Muichiro decides to change his attitude upon seeing the trainees' joy when flying their own planes.