It has always been a mystery why Summer Sonic is not held in the relative cool of June or July, but at the very height of summer, when the August sun beats down upon the festival's outdoor stages or typhoons power through the country, threatening disruption and cancellations to the event's packed schedule.

And yet, each year, countless music lovers descend upon the Tokyo and Osaka iterations of the three-day festival, which this year celebrated its 20th anniversary before a planned hiatus for the 2020 Tokyo Olympics.

Though actual celebrations of the anniversary were in short supply on the ground, this year's lineup was a bumper one, with a plethora of stadium-filling acts on a roster with excellent depth, including international superstars Red Hot Chili Peppers, home favorites Sakanaction, kawaii-metal darlings Babymetal, pop-duo The Chainsmokers and B'z, the best-selling Japanese group in history.