Kaikai Kitan

"Kaikai Kitan" (Japanese: 廻廻奇譚; lit. 'Round Round Mysterious Story') is a song by Japanese singer Eve, released on October 3, 2020, through Toy's Factory. It served as the first opening theme for the anime Jujutsu Kaisen.

The track was Eve's first release in ten months. After learning his song would open the anime, Eve—a longtime reader of the manga—said he was "impressed" and reflected on how the protagonist Yuji Itadori's life and battles resonated with him. To create the music, he reread the entire manga series to refine his vision of the story. He initially produced a 90-second demo, then expanded the chorus with a large, chorus-like development at the anime director's request, aiming for a "violent" melody. Eve noted that his naturally light voice required him to figure out how to deliver a heavy, dark, and fast-paced song, calling it a deeply felt piece.

Musically, "Kaikai Kitan" is an upbeat track with a fast, heavy sound and a dramatic melody. The first verse relies on a quick band sound with solid guitars, while the second verse's A-melody shifts to a trap-influenced mid-tempo groove. The lyrics weave in elements of Jujutsu Kaisen's plot, with phrases that echo the fate of protagonist Yuji Itadori and hint at future events.

The music video, directed by Yuichiro Saeki, features anime footage and was released on YouTube on November 20, 2020. It surpassed 100 million views on April 13, 2021, and a live video presentation was uploaded on March 26, 2021, to mark the milestone.

Critics praised the song. Satoru Ryusei of Real Sound noted that it blends a typical anime song sound with the light and dark sides of sorcerers who move forward despite dark pasts. Kari Komatsu of Rockin' On described the under-four-minute track as packed with sounds and arrangements, including effective vocal effects, that vividly capture the struggle to navigate a chaotic world. The song also influenced Tatsuya Kitani when he wrote the opening for Jujutsu Kaisen's second season, "Where Our Blue Is".