J-Pop trainee, 8, dies of flu-triggered heart inflammation FIVE DAYS after her final concert

From the Newshound archive · first published 30 September 2026 · last updated 1 October 2026.

Hirata Runa, known as Luna-chan, was eight years old when she died at around 4am on Friday from myocarditis triggered by influenza — just five days after appearing at the DIANNA Project's Regular Live Vol.70 concert in Nagoya, Japan. Her agency announced the death and confirmed that a private wake and funeral had already been held, attended only by close relatives. Her last social media post, written immediately after that final performance, read: 'It was so much fun. I hope the people in part three have fun too.'

Her family said 'a third of Runa's life was as an idol' and asked fans to 'let her stay in a corner of your hearts as an eternal idol.'

Fellow trainee Miyata Ryoka described herself as 'at a loss for words' upon hearing the news, as tributes poured in beneath Runa's final post.

Runa's agency urged the public not to make private inquiries or raise questions about the circumstances of her death on social media.