Zone is the solo debut mini album by Jihyo of TWICE, released August 18, 2023 via JYP Entertainment and Republic Records — making her the second TWICE member to release a solo Korean album after Nayeon. The album title combines the letter Z (from her nickname "Zyo") with "One," meaning both her first work and a complete world of her own. It comes in four versions — Z, Y, O, and a digipack — with the standard three versions each containing a photobook, CD, 2 photocards (2 of 12), message postcard (1 of 3), interview mini book (1 of 3), bookmark (1 of 3), lyrics sticker pack, and folded poster (1 of 3). Pre-orders added a photo film and additional poster per version. Limited vinyl editions followed in November 2023. The 7-track R&B and dance-pop album is notable for Jihyo's extensive creative involvement: she composed four tracks and wrote lyrics for six, with "Closer," "Room," and "Nightmare" entirely self-written, and "Don't Wanna Go Back" co-written with duet partner Heize. "Talkin' About It" featuring American rapper 24kGoldn marks the first collaboration between any TWICE member and a Western artist on a solo release. An English version of "Killin' Me Good" followed digitally on September 15. The album sold 534,565 first-week copies on Hanteo — the third-highest first-week sales by any female soloist in Hanteo history at the time — debuted at #14 on the Billboard 200, and was certified Circle Chart 2× Platinum.