ARTISTYabai T-Shirts Yasan

Yabai T-Shirts Yasan formed in 2013 among fellow members of a club at Osaka University of Arts. Based in Osaka, the group is a three-piece band with male and female vocals, comprising Takuya Koyama (guitar and vocals), Aribobo (bass and vocals), and Morimorimoto (drums and chorus). Since its 2016 debut, the group has released music and performed on tours and at festivals around Japan. Its concert venues have included Osaka-jō Hall and Nippon Budokan.

The biography names «ハッピーウェディング前ソング» and «かわE» among the group’s songs; their total play counts have exceeded 130 million and 100 million, respectively. In 2023, the group began singing on television and, on November 15 of that year, released a best-of album marking its tenth anniversary. It performed at Shima Spain Village on May 11 and 12, 2024. On May 10 and 11, 2025, it held its first self-organized outdoor festival and outdoor concert there, titled «ヤバイ T シャツ屋さん “Tank-top Festival 2025” in 志摩スペイン村», drawing 16,000 people over two days. In 2026, the group returned to the same venue for the festival and concert, drawing 18,000 people over two days.