Regret (Hoshimura Mai)
- Hoshimura Mai
- Catalog Number
- Love Tuning (ラウ゛・チューニング)
- Sakura Biyori x Oshio Kotaro (桜日和 × 押尾コータロー; Cherry Blossom Weather)
- regret (D.Gray-man Ending Ver.)
- regret (Instrumental)
"regret" is the 14th single (13th major label single) released by Hoshimura Mai. The title track was used as the seventh ending theme song for the anime D.Gray-man. "Sakura Biyori x Oshio Kotaro" is an acoustic version of her previous-released song, "Sakura Biyori". The single reached #30 on the Oricon weekly charts and charted for 4 weeks. It sold 3,465 units on its first week and 6,313 units totally.