Tō no Chūjō, Genji's brother-in-law as brother to Lady Aoi, Genji's first wife, shares a lifelong close friendship with him. They often gather to reminisce and play music, yet their bond remains threaded with rivalry.

In youth, this rivalry focused on romantic conquests, especially their competition for the court lady Naishi. Though recognized as handsome and skilled in dance, poetry, and courtly duties, Tō no Chūjō is consistently eclipsed by Genji's extraordinary talents and charisma. He is famously likened to a "nondescript mountain shrub" beside Genji, the "blossoming cherry."

As a mature statesman, Tō no Chūjō redirects his rivalry to politics and society. He actively promotes his daughter, the Kokiden girl, to marry Emperor Reizei, pitting her against Genji's choice, Akikonomu, in a palace contest centered on the artistic merits of their female factions. His character displays pragmatism and rigidity; he initially dismissed his former lover Yūgao, mother of his child, as timid and unremarkable. Genji later challenges this view upon discovering Yūgao's gentle charm. After her tragic death, Genji cares for her attendants and child, implicitly criticizing Tō no Chūjō's prior treatment.

Despite their competition, Tō no Chūjō shows steadfast loyalty to Genji during critical times. When political schemes by Lady Kokiden lead to Genji's exile to Suma, Tō no Chūjō openly defies court orders forbidding contact. He risks his own diminished status—stemming from his father's retirement—to visit Genji, demonstrating their bond's depth.

In later years, Tō no Chūjō becomes Genji's primary confidant and frequent companion, their interactions revolving around shared memories and musical performances. His daughter, the Kokiden girl, ultimately marries not Reizei but his successor, Emperor Suzaku, securing Tō no Chūjō's influence at court.