Jun Hamaguchi (浜 口淳, Hamaguchi Jun) was a student in Yomiyama North Middle School's 9th Grade Class 3 in 1983 along with Reiko Mikami, Katsumi Matsunaga, and Yuki Hoshikawa.

Jun had short dark brown hair and dark brown eyes.

He was seen wearing the standard male school uniform.

On the school trip in 1983, Katsumi's class visited the Yomiyama Shrine. After praying at the shrine, Class 3-3's teacher, Mr. Koga, declared everything would be okay and the class was free from the curse, much to the relief of Jun and his classmates. After leaving, the sky turned overcast, and it began to rain. Everyone left the shrine, and Katsumi was walking behind Jun. Jun was the only one who brought an umbrella, and lightning struck him, killing him instantly. When Katsumi opened his eyes, he said that he could smell Jun's flesh burning. His death caused the students to run down the mountain in terror, which in turn led to Yuki Hoshikawa slipping and tumbling down the mountain to her death.