School Days is the second single by Guardians 4. The single was released on September 2, 2009 in two editions: regular and limited. The single V was released on September 16, 2009.
"School Days" was used as the fourth opening theme song for the anime Shugo Chara! Doki—. A version sung by Shugo Chara Egg! is also included as a coupling track.
The single reached #8 on the Oricon charts and charted for four weeks, selling 11,673 copies. The single V peaked at #13 on the Oricon charts and sold 2,014 copies.
