優しさの理由

Yasashisa no Riyuu (優しさの理由) is a song by ChouCho that served as the first opening theme for the 2012 television anime Hyouka (氷菓), produced by Kyoto Animation. Lantis released it on May 2, 2012 as ChouCho's debut single.

こだまさおり wrote the lyrics, 宮崎誠 composed the music, and 虹音 arranged the song. The single also included "木漏れ日色の記憶" and "青空の鼓動" alongside off-vocal versions of all three tracks, and the title song later appeared on ChouCho's first album flyleaf, released on November 27, 2013.