BUT / Aishou (愛証 / Love Proof) is singer-songwriter Koda Kumi's 35th single and was released on March 14, 2007. It was her first single of 2007 and first to bring her new era, Kingdom. The single was a limited purchase, only being sold from March 2007 to May 2007. It charted No. 2 on Oricon and stayed on the charts for fourteen weeks. The single was released the same day as her third compilation album, Best ~Bounce & Lovers~, which was also of limited release.

Kumiko Kōda , known professionally as Koda Kumi , is a Japanese singer from Kyoto, known for her urban and R&B songs.