Strange things were afoot in July as teenagers congregated in churchyards. Cars crashed as drivers stared at their smartphones. And Clash Royale — among the highest grossing games apps since its launch last March — suddenly dropped out of the top 10. One cause of all these events was the launch of Pokémon Go — the mixed-reality mobile game that superimposed animated characters on to the real world for gamers to chase around cities and along roads, and had 50m players at its peak. It also caused an almighty pain for Ilkka Paananen, the 37-year-old co-founder and chief executive of Supercell, the Finnish gaming studio behind Clash Royale and Clash of Clans. Pokémon Go’s success “was a kick in our butt”, he says.

More than 100m people still play Supercell games daily, and it remains the world’s biggest mobile video game publisher by revenues. Its success is the stuff of legend — many games studios have proven one-hit wonders; Supercell has had four. In 2012, it released its first two games, Hay Day and Clash of Clans, both of which went on to generate more than $2m a day within a year, through its “freemium” model, which allows anyone to play for free, but requires in-app payments to advance through the levels. But in July, Clash Royale raked in an estimated $62m, roughly half of what it was making in April, according to SuperData Research. Pokémon Go was not the only problem either. Supercell had no games in the top 10 last summer.

Mr Paananen got a lot out of the experience — particularly new knowledge about how to fight business threats. His main realisation was that “we weren’t good at listening to our users”, he says. So after Supercell fell out of the top 10, the studio mobilised, thrashing out user feedback in troubleshooting meetings.