Draft:Sequence 01: Curiosity

On December 8, 2025, Jellyfish Entertainment announced that Yoo Seung-eon and Ji Yun-seo would leave the boy group Evnne following the conclusion of their contracts with the company and return to their original agency, YH Entertainment. The group would continue activities as a five-member group from 2026, consisting of Keita, Park Han-bin, Lee Jeong-hyeon, Mun Jung-hyun, and Park Ji-hoo.^[1] Entertainment company WakeOne announced on February 12, 2026, that the boy group Zerobaseone would continue activities with five of its original nine members: Sung Han-bin, Kim Ji-woong, Kim Tae-rae, and Park Gun-wook. The remaining members, Zhang Hao, Ricky, Kim Gyu-vin, and Han Yu-jin, all of whom were signed to YH Entertainment, would pursue activities independently of the group. The announcement followed an initial two-month extension of the group's contract, with the nine-member lineup continuing activities until March, when they held their final concert at the KSPO Dome in Seoul.^[2]

On March 18, Ilgan Sports reported that the former Zerobaseone members Zhang Hao, Ricky, Kim Gyu-vin and Han Yu-jin would be part of YH Entertainment's then-upcoming boy group Andouble. YH Entertainment confirmed to Maeil Business that the four members were preparing for their debut, with further details to be announced later.^[3] The former Evnne member, Yoo Seung-eon, was later added to the group's lineup, with its agency confirming the news to Newsen on April 3. The group's scheduled debut date was also revealed to be May 26.^[4] The group's official name, And2ble, was unveiled on May 1, following the opening of its Instagram account, with other social media channels following on May 6.^[5] The title of the group's debut EP, Sequency 01: Curiosity, was announced on April 27.^[6]

Sequence 01: Curiosity was released on May 26, 2026, on music download and streaming platforms by YH Entertainment under license to Kakao Entertainment,^[7] alongside its single "Curious".^[8] A physical release of the EP was issued on CD in South Korea the same day,^[9] with a release in Japan occuring on June 5 via Sony Music Japan.^[10]

Sequency 01: Curiosity features five tracks, with three of the group's members participating in the writing of lyrics, while its production remained largely outsourced, with most of the work being handled by outside collaborators.^[12] It features music production team the Stereotypes in the composition and arrangement of three tracks.^[13] The opener of the EP, "Curious", is an EDM song, featuring elements of synth pop and future house.^[14][12] Its lyrics were written by Ricky and Zhang Hao, alongside Lee Seu-ran. The lyrics of "Aura" were written by Lee, Ricky and Nevada, and the track features elements of pop-R&B, with synths, hushed vocals and a slower tempo.^[12][15] "Sugar Rush" is a dance-pop bubblegum track with lyrics written by Im Su-ran, Kim Gi-tae and Moon Ji-young about physical attraction, featuring guitar elements.^[12][15] "Bed" is an acoustic pop song, with lyrics written by Jeong-seon, Moon and Sam Carter, featuring the group singing in their falsetto register.^[15][8] The EP's closer and alternative pop song, "Happy &", had its lyrics written by BrotherSu and members Zhang and Kim Gyu-vin, with the group singing about the celebration of new beginnings.^[12][15]

Clockwise from top left: The chorus of "Curious" was compared to fellow K-pop acts TVXQ, Shinee and Exo.

Writing for TV Daily, Kim Jin-seok described Sequence 01: Curiosity as a "captivating first step", praising its trendy and alluring mood, while Kim Han-gil highlighted the contrast in moods between the EP's songs. Kim Ji-ha described it as a "clever debut work".^[16] In a review of "Curious" for IZM, Shin Dong-gyu rated the song one and a half stars, comparing its chorus to those of other K-pop acts such as Shinee, Exo and TVXQ, calling the track's attempt at establishing their own identity as something "difficult to believe".^[17]

Nancy Jiang of Billboard Korea described the EP as reminiscent of K-pop's "third generation", and saying its sound "borders on reverence" for that era. Jiang also highlighted the member's individual skills, including Yoo Seung-eon's high vocal register, which was complemented by Zhang Hao's "warmer" tone. Ricky's R&B-leaning vocal delivery was also praised, alongside the smoother tones of Kim Gyu-vin and Han Yu-jin.^[12]

Two editions of Sequence 01: Curiosity placed on South Korea's Circle Album Chart: the standard edition debuted at number 2 with 471,090 units sold, while the Poca edition debuted at number 5 with 135,000.^[18] The standard edition also charted on the monthly chart in June–July 2026 at number 6 and 13, respectively,^[19][20] while the Poca edition charted in May and July at number 18 and 31, respectively.^[21][20] It also placed in the chart's 2026 first-half issue, with the standard edition at number 22 and the Poca edition at number 74, with each version selling 612,687 and 135,000 units, respectively.^[22] The album has been certified 2× Platinum by the Korea Music Content Association for selling over 500,000 certified units.^[23] Internationally, the album debuted at number 6 on Japan's Oricon Albums Chart,^[24] peaking at number 4 the following week.^[10] It also charted on its monthly issue, debuting at number 14 after selling 24,134 units.^[25]

The EP's single, "Curious", charted on South Korea's Circle Digital Chart, peaking at number 65.^[26] It also debuted at number 2 on the Circle BGM Chart and number 8 on its monthly edition during May.^[27][28] On the Circle Download Chart, all five tracks charted, with "Curious" debuting at number 2, followed by "Aura" at number 23, "Sugar Rush" at number 26, "Happy &" at number 29, and "Bed" at number 30.^[29] All five tracks also charted on the monthly edition in May, with "Curious" at number eight, "Aura" at number 162, "Sugar Rush" at number 188, "Happy &" at number 192, and "Bed" at number 194.^[30]

The credits were adapted from the EP's liner notes and Apple Music.^[13][7]