Heisei period
During a KAT-TUN spring concert on April 3, 2007, Yuya Takaki, Daiki Arioka, Ryosuke Yamada, Yuto Nakajima and Yuri Chinen were announced to become part of a temporary group called Hey! Say! 7. The name refers to the Heisei period during which all members were born, as well as to the year 2007 as the group's formation year.