Terukichi Miyata, often called "Uncle Teru," is the wealthiest man on Uta-jima, owning two large lumber freighters and wielding considerable influence. His wealth and status are relatively recent, built from nothing through decades of toil and determination. This self-made background shapes his identity as the embodiment of the island's ambition, strength, and resilience, described as "the personification of all of Uta-jima’s toil and determination and ambition and strength."

He possesses extensive maritime expertise, including uncanny weather prediction, deep knowledge of fishing and navigation, and a strong grasp of island history and traditions, reflecting his lifelong connection to the sea. However, his character exhibits flaws: uncompromising stubbornness, "ludicrous pretensions," and pugnacity. It is suggested that while he learned nature's lessons in youth, he occasionally acts as "a bronze statue erected to his own memory" in old age.

After the death of his wife and only son, Terukichi recalls his youngest daughter, Hatsue, from her pearl-diving apprenticeship. He announces plans to adopt a young man for her to marry, continuing the Miyata lineage, underscoring his prioritization of family legacy and social standing.

Discovering Hatsue's involvement with Shinji Kubo, a poor fisherman's apprentice, Terukichi reacts with rage, especially after rumors they slept together. He forbids Hatsue from seeing Shinji and threatens to marry her to Yasuo Kawamoto, the son of a prominent family, highlighting his class-consciousness and initial insulation from his daughter's needs.

Terukichi's character develops when his daughter's persistent sadness penetrates his resolve. He devises a practical test, employing Shinji and Yasuo as apprentices on his freighter, the Utajima-maru, during a voyage to Okinawa. During a severe typhoon, Shinji demonstrates extraordinary courage and "get-up-and-go," risking his life to secure a lifeline to a buoy and saving the vessel, while Yasuo proves cowardly and ineffective. This event leads Terukichi to reassess his values.

Consequently, Terukichi reverses his position, approving Shinji as Hatsue's husband. He declares that "the only thing that really counts in a man is his get-up-and-go," valuing Shinji's courage over Yasuo's wealth or connections. His transformation culminates in offering to welcome Shinji's mother and younger brother, Hiroshi, into the Miyata household, reflecting his capacity for growth, wisdom, and underlying generosity, despite his salty, judgmental, and narrow-minded demeanor.