Kingdom Hearts Unchained χ features plot and gameplay elements from the Japan-exclusive web browser game Kingdom Hearts χ, and is free to play, but contains in-app purchases. Kingdom Hearts Unchained χ was released in Japan on Septemand in North America on April 7, 2016. During Square Enix's E3 Conference on June 16, 2015, a trailer for the game was released showcasing gameplay. Kingdom Hearts Unchained χ, later renamed as Kingdom Hearts Union χ, is a Kingdom Hearts game exclusive to the iOS and Android smartphone platforms/mobile devices and was first announced on May 12, 2015.