A 14-year-old in Japan is typically in Junior High 3 (the third year of junior high school).
The Japanese school system is structured as follows:
- Elementary School: 6 years (ages 6-12)
- Junior High School: 3 years (ages 12-15)
- High School: 3 years (ages 15-18)
- University: 4 years (typically)
Therefore, a 14-year-old, being in the third year of Junior High, would be in Junior High 3. According to the Kyoto International School Grade Placement Chart, a 14-year-old corresponds to Junior High 3 in the Japanese system.
