"No Regret" is an R&B song by singer-songwriter Koda Kumi. The song debuted on the Oricon charts at #4, remaining on the charts for twelve weeks. The single made it the eighth release for her 12 Singles Collection, and, unlike the majority of the singles, was not limited to 50,000 copies. This was one of three that were not limited, the other being the first single in the collection, you, and the final single, Someday/Boys♥Girls.

No Regret is Japanese singer-songwriter Kumi Koda's eighth single in her 12 Singles Collection and twenty-sixth overall. It managed to peak at #4 on the Oricon Singles Charts and remained on the charts for twelve weeks. Unlike most of the other singles in the collection, No Regret was not limited to 50,000 copies. This was only done with two other singles in the collection: you and Someday/Boys♥Girls. No Regret sold 72,081 copies within the first week and, as more recent figures show, it has sold a total of 131,348 copies.

Each single in the 12 Singles Collection had unique cover art based on certain cultures in various countries. The back cover of each single was a piece to a puzzle, which could only be completed by purchasing all twelve singles. The same was done for the obi strips, which contained a full image when arranged together in order. However, the obi strip image was omitted on the Hong Kong versions.

"No Regret" is a blend of R&B and electronic dance music. The music was composed and performed by musical composer h-wonder, who had previously composed the bulk of the music for Kumi's debut studio album affection, and the lyrics were written by Toru Watanabe, who had written the musical score to the first single in the 12 Singles Collection, "you." The b-side to the single was an alternate version of "Rain," the original which had previously been released on her third studio album, feel my mind. However, while the b-side was an alternate version, the instrumental for the piece was that of the version originally placed on the 2004 album.

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