and operating system functionality. The first such game that demonstrated the desire for handset games was a version of Snake that Nokia had included on its devices since 1997. In 1999, NTT Docomo launched the i-mode mobile platform in Japan, allowing mobile games to be downloaded onto smartphones. Several Japanese video game developers announced games for the i-mode platform that year, such as Konami announcing its dating simulation Tokimeki Memorial. The same year, Nintendo and Bandai were developing mobile phone adapters for their handheld game consoles, the Game Boy Color and WonderSwan, respectively. By 2001, i-mode had users in Japan, along with more advanced handsets with graphics comparable to 8-bit consoles. A wide variety of games were available for the i-mode service, along with announcements from established video game developers such as Taito, Konami, Namco, and Hudson Soft, including ports of classic arcade games and 8-bit console games. The launch of Apple's iPhone in 2007 and the App Store in 2008 radically changed the market. The iPhone's focus on larger memory, multitasks, and additional sensing devices, including the touchscreen in later model, made it ideal for casual games, while the App Store made it easy for developers to create and post apps to publish, and for users to search for and obtain new games. Further, the App Store added the ability to support in-app purchases in October 2009. This allowed games like Angry Birds and Cut the Rope to find new monetization models away from the traditional premium "pay once" model. Meanwhile, Apple's disruption caused the market to stabilized around iPhone devices and Google's Android-based phones which offered a similar app store through Google Play. A further major shift game with 2012's Candy Crush Saga and Puzzle & Dragons, games that used a stamina-like gameplay feature found in social-network games like FarmVille to limit the number of times one could play it in a single period, but allowed optional in-app purchases to restore that stamina immediately and continue playing. This new monetization brought in millions of players to both games and millions of dollars in revenue, establishing the "freemium" model that would be a common approach for many mobile game going forward. Mobile gaming grew rapidly over the next several years, buoyed by rapid expansion in China. By 2016, top mobile games were earning over a year, and the total revenue for the mobile games sector had surpassed that of