The central pair behind electronic project AmPm didn't have high expectations when they flew to Jakarta last August for Spotify On Stage, a live event organized by the market-leading music streaming service.

"We were the first act up, and I think most of the audience came to see other artists," says "K," one half of the unit. "But when our picture came up on screen, they made so much noise. When our music started, everyone sang along. They must have listened to the event playlist beforehand and memorized the lyrics."

Their set in Indonesia's capital, opening an evening headlined by K-pop heavyweights NCT127 and American pop group DNCE, was a high point in a year where AmPm (pronounced like "um palm") possibly scored the biggest international hit of the year from a Japanese artist. You may not have noticed as the project lacks a cooky concept like Babymetal's idol-meets-metal proposition, or a viral video like Pikotaro's "PPAP."