Revealed: Secret Strategies of World’s Most Lucrative Apps

A few months ago, Yoshiki Watabe, a producer at Japan’s DeNA Co., was looking to draw attention for the company’s hit mobile game. He introduced a spiky-haired hero armed with an outsized sword -- then gave players a mere four days to bring down an evil megacorporation.

It worked. Final Fantasy Record Keeper climbed in download and revenue rankings. It’s an example of how Japanese publishers have become the best in the world at making money from free mobile games. They use psychology, art and big data to get customers to come, play and pay for digital extras like weapons or skills.