YUI grew up in a single parent family and so does not have any memory of her father. She does remember always being close to music, be it from her mother’s car stereo or the radio; she would remember the tunes and sing along. By the time she was in elementary school she thought she would like to become a singer.
During her third year in middle school, following the influence of her mother, YUI began keeping a journal of everyday feelings and poetry. Because of this, by the time she was in high school, she began writing songs. While in high school she worked part-time to help pay for tuition. Always busy, she thought there was no longer a road to music. Eventually she became ill. While in hospital, with time to think, she was overwhelmed with the desire to make music. She decided that school and music could not coexist. Upon leaving the hospital she encountered a live street performance and expressed her desire to pursue a musical career to the band, Bianco Nero, at the end of the concert. Bianco Nero recommended to YUI that she should join a private music school and soon, she dropped out of high school and seriously began studying songwriting and guitar at a juku in her hometown of Fukuoka. Aspiring to become a professional, she carried her guitar around and sang at the entrance of Tenjin Station in Fukuoka. Doing these street performances helped YUI to eventually overcome her shyness.