To. X

'To. X' is the fifth Korean-language extended play and eighth overall by South Korean singer Taeyeon. It was released by SM Entertainment on November 27, 2023, and contains six tracks, including the lead single of the same name.

Background and release
On November 6, 2023, SM Entertainment announced Taeyeon would be releasing her fifth Korean extended play titled ''To. X'' on November 27. Two days later, the promotional schedule was released. On November 13, the mood sampler teaser video was released, followed by the highlight teaser video three days later. The highlight teaser video for "Burn It Now" was released on November 20, with "Melt Away" on November 21, followed by "Nightmare" on November 22, and "All For Nothing" on November 23. On November 24, the music video teaser video for "To. X" was released. The extended play was released alongside the music video for the lead single on November 27.

Composition
''To. X'' contains six tracks. The lead single, "To. X", is a R&B song that "combines sensuous guitar riffs and rhythmic melodies" with lyrics carrying the message of "[Taeyeon singing] about the end of a controlling relationship after realizing that the other person is controlling her". The second track, "Melt Away", is a R&B song that "combines sensual guitar riffs, trumpets, and percussion" with lyrics containing "a sense of leisure, arrogance, and confident that one can melt the cold heart of the other person". The third track, "Burn It Down", is a pop ballad song featuring "addictive guitar riff" with lyrics about "complaining that everything has been ruined as if everything was burned down by the other person who only hurt them under the guise of love". The fourth track, "Nightmare" (악몽), is a pop ballad song characterized by "simple acoustic guitar riff" with lyrics about "leaving without regrets after a sharp rebuke to the other person who was showing a weak side". The fifth track, "All For Nothing", is a pop ballad song with lyrics written by Taeyeon about "honestly express[ing] the feelings of being hurt by the other person who gave up everything". The final track, "Fabulous", is a R&B song with "jazzy and captivating atmosphere" characterized by "grand and colorful string and trumpet rhythm", its English lyrics describe "the feeling of self-confidence that everyone envies but at the same time feeling in danger".

Commercial performance
''To. X'' debuted at number three on South Korea's Circle Album Chart in the chart issue dated November 26 – December 2, 2023 and ascended to number two on the Circle Album Chart in the following two weeks; on the monthly chart, the EP debuted at number 14 in the chart issue for November 2023. In Japan, the EP debuted at number 50 on the Billboard Japan Hot Albums in the chart issue dated December 6, 2023; on its component chart, it debuted at number 20 on the Top Download Albums. On the Oricon chart, the EP debuted at number 19 on the Digital Albums Chart in the chart issue dated December 11, 2023. In the United Kingdom, the EP debuted at number 93 on the OCC's UK Album Downloads Chart in the chart issue dated December 1–7, 2023.

Promotion
Prior to the release of ''To. X'', on November 27, 2023, Taeyeon held a live event called "Taeyeon 'To. X' Countdown Live" on YouTube, TikTok, Weverse, and Idol Plus, aimed at introducing the extended play and connecting with her fanbase. Additionally, a pop-up store named "Letter 'To. X' Concept Room" was opened in Seoul, South Korea, running from November 27 to December 3. The live performance clip for "All For Nothing" was released on December 6, followed by "To.X" on December 8, and "Fabulous" on December 11 while the lyric video for "Nightmare" will be released on December 15, presented through her YouTube channel.