"One of These Nights" (Korean: 7월 7일; RR: 7 wol 7 il; lit. "July 7") is a song recorded by South Korean girl group Red Velvet. Composed by Hwang Chan-hee, Andreas Öberg, Maria Marcus and penned by Seo Ji-eum of Jam Factory, it was released as the lead single from their second extended play, The Velvet, which is also the group's first major release to focus on the 'Velvet' half of their unique dual concept, as a follow-up to their last album, The Red. "One of These Nights" is an R&B mid-tempo song with lyrics inspired by the story of Jingnyeo and Gyeonu, a folk tale conceived from the Korean festival Chilseok which originates from the Chinese Qixi Festival which falls on the seventh day of the seventh month on the lunisolar calendar. Originally intended to be released a day earlier, SM Entertainment delayed the song and album's release to March 17, 2016, to ensure its quality. The single received generally favorable reviews from music critics who compared the song to the group's more upbeat releases, but praised the transition which was hailed as a bold move at a time when K-pop artists commonly aimed to release the catchiest dance hit. It was fairly successful in the group's native country South Korea, becoming their fourth top-ten hit on the Gaon Digital Chart and number six on Billboard's World Digital Songs chart.