During the next year, Taeyeon accompanied her father from their hometown to Seoul on every Sunday to receive her vocal lessons from The One. In a interview, he described Taeyeon as a "smart" student, someone "unlike others who came to him with dreams of becoming a celebrity She first contributed her vocals to "" featuring Kangta , a track taken from both Girls' Generation's eponymous debut album and Kangta's fourth studio album, Eternity She was cast in a lead role in the musical Midnight Sun , an adaptation of the Japanese novel of the same name Having learned the guitar for her character portrayal, she played the part of Kaoru Amane, a teenager who suffered from xeroderma pigmentosum.
Her performance in the sold-out shows received good press despite the musical's critical reviews. Goddess of War soundtrack, reached number two on the same chart. I was moved to tears listening to her singing. Their debut EP , Twinkle , met with much success and became South Korea's 8th highest selling album of the year. Holler and Dear Santa Go soundtrack, after its musical director was left with a "deep impression" having heard her cover version of a song during a radio appearance.
Solo debut with I and Why Taeyeon began working on a solo album in late , believing her "right time" had come. She previously was afraid of not being ready for a solo debut, but her eight-year career proved to help her gain the experience to be "well-prepared". M Entertainment launched a digital music platform called SM Station , having Taeyeon's single " Rain " being its first release. It remained to be the most commercially successful song of SM Station to-date. The album met with complimentary reviews, with Jeff Benjamin from Fuse praising Taeyeon's "powerful vocals" in it.
It was deemed by the media as a success, setting a precedent in a Korean market which stigmatized concerts held by a single girl group members on the basis that they could not be profitable. Scarlet Heart Ryeo ,  her next single, " It peaked at number 2 on Gaon Digital Chart and was chosen by Billboard as the seventh best K-pop song of the year.
My Voice Taeyeon's first studio album , My Voice , being in the production process for over a year, was released in February and spawned a single titled " Fine ". It is exclusive to members of S. Entertainment's official Japanese fan club.
Her debut single "I" departs for a pop rock sound. If you can feel a deep soul from a singer, that's 'K-Soul'.