Nagasaki is making his first Championship start in 2025. In June, he earned co-medalist honors in the Toyota Junior World Cup in Japan and helped his country earn the team title with older brother Koshin and 2024 Japan Amateur champion Mao Matsuyama. He also finished runner-up in the Japan Amateur Championship and fourth in both the Royal Junior in Japan and the Chinese Taipei Amateur earlier this year. In 2024, he won the Boys 12-14 division of the Japan Junior Championship and finished runner-up to India’s Kartik Singh in the Boys 13-14 division of the Junior World Championships in San Diego.