Epic Games Inc.’s decision to sue Apple Inc. over its mobile store practices has sparked new scrutiny in the massive Japanese gaming market, prompting complaints and questions about how to counter the tech giant’s dominance. While Epic, publisher of the hit title Fortnite, focuses on the 30% revenue cut app stores typically take, Japanese game studios have broader concerns. They have long been unhappy with what they see as Apple’s inconsistent enforcement of its own App Store guidelines, unpredictable content decisions, and lapses in communication, according to more than a dozen people involved in the matter. Japan’s antitrust regulator said it will step up attention to the iPhone maker’s practices in the wake of the high-stakes legal clash. And in rare cases, prominent executives are beginning to speak out after staying silent out of fear of reprisal. “I want from the bottom of my heart Epic to win,” Hironao Kunimitsu, founder, and chairman of Tokyo-based mobile game maker Gumi Inc. wrote on his Facebook page. Apple and Google hold a duopoly over the mobile app market outside China. Any publisher that wants a game to be played on iPhones or Android devices is effectively forced to distribute it via their app stores, sharing revenue from an initial purchase and future, related items. Epic, whose Fortnite generates more than $1 billion annually from in-game purchases of virtual cosmetics and extras, sued both companies for what it considers excessive fees and for the right to sell game extras directly to players. Apple and Google have disputed those charges in court. The iPhone maker argues its cut is justified by its provision of security, development support, and an audience of a billion users. The iPhone is a huge revenue driver for game creators in Japan, including established names like Square Enix Holdings Co., which gets 40% of its group revenue from smartphone games, and Bandai Namco Holdings Inc. Sony Corp. has a multibillion-dollar mobile hit called Fate/Grand Order. With 702,000 registered developers, Japan is home to one of the most creative developer communities. A recent study commissioned by Apple estimated the App Store ecosystem in Japan generated $37 billion in billings and sales in 2019 -- $11 billion in digital goods and services, $24 billion via physical goods and services, and $2 billion from in-app advertising. Read more on OUR FORUM.