Kodomo vs. Otona: When Children Become Adults in Japan

As you may know, “Kodomo (子供)” means “child” in Japanese, while “Otona (大人)” is the word for “adult”.

Based on the definition by law, currently, children in Japan legally become adults at 20.

But as the Japanese government decided to lower the age of adulthood to 18 in 2018,

from April 2022, people living in Japan legally become Otona or come of age at eighteen.

When Kodomo exactly becomes Otona

At present, people over the age of twenty are regarded as adults or Otona or Seijin in Japan.

“Seijin (成人)” is the word for “legal adult”, but some legal adults or Seijin may not have become Otona yet and may have still been Kodomo.

Kodomo exactly becomes Otona when their thinking and attitude have matured.

So a 10-year-old kid isn’t a Seijin in Japan but can be called Otona if well-behaved.