Tokyo was announced to be implemented as the next city, coming to HKO in summer 2010. For more details of the announcement of April 28th 2010 click here: [1]
In Oct-Nov 2011, there was a Hello Kitty Birthday Bash: Tokyo Trip, which the top 20 players from the daily events could tour Tokyo. Screens were taken of the trip, but players were asked to not post them online. (A GM said not to, while another GM said they could.) However, it was decided to not post these Tokyo screens until Tokyo is ready to be opened, which is still unknown.