Prosecutors sought an 18-year jail term on Monday for the stepfather of 5-year-old Yua Funato over assault and neglect that led to her death last year in a high-profile child abuse case.

Yudai Funato, 34, is accused of causing the death of Yua from sepsis in March 2018. He allegedly limited the child's food intake from around late January last year, beat her and did not seek medical care despite her weakened state.

"The defendant led the severe abuse. He made the girl suffer from starvation by limiting food. He bullied the victim to such an extent that she had nowhere to escape," prosecutors said. "The crime's maliciousness is severe beyond comparison."