"Oh!" is the lead single from Oh!, the second studio album by South Korean girl group Girls' Generation. The single was digitally released on January 25, 2010 and came to be a huge hit song in South Korea. The group used a cheerleader concept for the song's promotional activities. The song hit #1 on various charts, and won several times on the Korean music chart shows Music Bank and The Music Trend. The song ranked #4 on Gaon Chart Top 10 Digital Songs of the Year and it was also the second best selling single in that year, selling over 3.3 million copies. Music site Monkey3 named "Oh!" the best song in 2010.

"Oh!" was remade as a Japanese song for the group's second single titled, "Oh!", from their second Japanese album Girls & Peace.. It was their fifth Japanese single. The music video for "Oh!" was released on September 14, 2012. Promotion for the single began on Hey! Hey! Hey! Music Champ. The single ranked highly among Japanese music charts, clinching the top spot on the Oricon Daily and Weekly single chart as well as the top spot on the Japanese Hot 100. The single was released with the song, "All My Love Is for You", on September 26, 2012, with an accompanying music video premiering on September 14, 2012.

Kenzie, a songwriter who previously composed the group's debut single "Into the New World", also composed "Oh!".

"Oh!" was released to digital music sites on January 25, 2010. The song quickly topped various digital music charts within 10 minutes of release. Moreover, the song reached #1 on Gaon Music Chart

On August 10, 2012, it was announced the group was to release their next Japanese single after the success of their previous single "Paparazzi", in the following month on September 26, 2012. The single was announced with no confirmation of title tracks, however fans were allowed to pre-order the regular, and limited editions of the single. After several weeks of speculation, the single's title track, a Japanese remake of the group's popular 2010 Korean hit, "Oh!" was finally announced on September 10. The accompanying music video to "Oh!" was released on September 14, 2012, along with an exclusive ringtone which was released at 5AM JST.

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