Kingdom Hearts χ was playable only in which country?

The original browser version of Kingdom Hearts χ was playable only in Japan.

Square Enix launched Kingdom Hearts χ as a Japanese PC browser game in July 2013. It served as a prequel set centuries before the main series, during the period leading up to the Keyblade War. Players created an avatar, joined one of five Unions, explored Disney-inspired worlds, and fought Heartless.

The country restriction applies specifically to Kingdom Hearts χ, not to every later version of the game. The browser title shut down in Japan in September 2016. Square Enix then brought its story and gameplay to mobile devices through Kingdom Hearts Unchained χ, which received releases in Japan, North America, and Europe.

That mobile version was later renamed Kingdom Hearts Union χ[Cross] and expanded the narrative beyond the original browser game. This distinction causes frequent confusion: Japan was the only country for the original browser release, while the related mobile successor became an international title.