Shuuhei Amamiya hails from a wealthy family with a distinguished lineage of professional pianists. His father, Youichiro Amamiya, is the renowned "Healing Pianist," and his mother, Namie Amamiya, actively supports his musical training. Immersed in this environment, Shuuhei began formal piano lessons at age four, practicing intensively for hours daily to develop considerable technical skill. Yet this upbringing framed piano performance primarily as a familial duty rather than a passion, resulting in technically precise but emotionally restrained playing that lacked personal expression.

As a transfer student to Moriwaki Elementary School, Shuuhei met Kai Ichinose, a classmate who played an abandoned piano in the nearby forest. When challenged to play this piano, Shuuhei couldn't produce sound, while Kai succeeded effortlessly. This encounter established their dynamic: Shuuhei respected Kai's innate musicality, seeing him as both a friend and rival. Their contrasting backgrounds—Shuuhei's privilege versus Kai's poverty—became a recurring theme, and through this friendship, the initially shy and cautious Shuuhei grew more assertive and willing to take creative risks in his performances.

Shuuhei won first place in Japan's 56th National Piano Competition. Despite this achievement, he faced growing self-doubt upon recognizing Kai's extraordinary natural talent. Heeding his father's advice and confronting his insecurities about Kai's genius, Shuuhei chose to study abroad in Austria. Overseas, witnessing a televised performance by Kai profoundly undermined his confidence, triggering a crisis in his musical identity. He temporarily returned to Japan, reuniting with Kai at Club P, where Kai performed disguised as a woman. There, Shuuhei helped Kai overcome a performance block by urging him to "think of the forest." This intervention simultaneously restored Shuuhei's own artistic self-assurance. Their reconciliation solidified their bond, and they decided to enter the International Chopin Piano Competition together.

Shuuhei's journey reflects his struggle to balance technical perfection with emotional authenticity. While Kai plays purely for personal fulfillment, Shuuhei habitually measures himself against others, particularly viewing Kai as both an inspirational figure and a source of insecurity. This dynamic drives his growth toward finding his unique artistic voice beyond family expectations.

Notable details include his childhood habit of wearing black gloves to protect his fingers during practice. He also shares a connection with his music teacher, Sosuke Ajino, as Shuuhei's father had previously attempted but failed to replicate Ajino's distinctive piano sound.