[5] On April 13, 1975, during the final concert of the band Carol led by Eikichi Yazawa, a firecracker explosion following the last song caused the stage to catch fire and burn down.

[1] On April 19, 1987, three people were trampled to death as the audience rushed to the stage at the beginning of a concert by Laughin' Nose.

[7] In 2013, Naon no Yaon was fully resurrected in conjunction with the 90th anniversary of Hibiya Open-Air Concert Hall and has been held annually since.

[10] Beginning in April and set to continue until November, around 40 performances are scheduled to be held at the venue in 2023 in celebration of its 100th anniversary.

[1] The Tokyo government decided to rebuild Hibiya Open-Air Concert Hall in 2021.