Kengo Satake allegedly stabbed his son, Ryota, an elementary school student, in the chest with a kitchen knife in their apartment in the central city of Nagoya on Sunday morning.
The son was confirmed dead from loss of blood an hour later.
“I stabbed him as he did not study,” the 48-year-old father told police.
Satake had reportedly wanted his son to pass an entrance examination for the same private junior high school in Nagoya from which he had graduated.
Japan’s “exam war” to get into prestigious schools has become increasingly intense as more and more parents push their children to take entrance examinations for reputable junior high schools.