The first "Tamagotchi" was released in 1996 as a mobile digital pet. This game became popular in Japan. From 1997 to 1998 other types of Tamagotchi game were released. About 40 million games sold around the world. In 2004, "Tamagotchi"' became popular again. The 2004 version of the game had infrared communication. The 2006 version could connect with mobile phones and personal computers. In 2006, a "Tamagotchi"-themed school game was released. In this game, the player could make a class using a communication function. In 2007, Tamagotchi started to live with its family in the device. In 2008, the game was released with a colored screen and download items and mini games. In 2012, the communication function was made more complicated.