Samsung appears to be following their previous trend of offering multiple different color variations of their flagship device in different markets. A new "Blue Arctic" version of the Samsung Galaxy S4 has been spotted in "the Land of the Rising Sun." There's no word on if this new variant colored SGS4 will ship anywhere besides Japan, but we will keep a lookout for you guys. Here's a quote with a few more details,

DoCoMo appears to be the first mobile operator in the world to sell the Blue Arctic Galaxy S4 version, with a launch reportedly set for the following weeks. Rbmen says that the handset will be announced by DoCoMo on May 15 and released in mid-May (therefore very close after being unveiled?), but nothing is official just yet.
More than likely different colors will slowly start to filter out to different areas of the globe if past patterns of behavior from Sammy are a good example.

Source: AndroidAuthority