As with every other smartphone announced today as part of Docomo's summer lineup, the SX runs Android 4.0 and is all the better for it. While it has been skinned by Sony and Docomo, of course, it's pretty tastefully done and doesn't seem to slow the phone down much, if at all. Unlike the Xperia S, the SX has onscreen buttons, but otherwise the software effort bodes well for the Ice Cream Sandwich update coming to its bigger brother in the next few weeks. There's no word yet on whether the SX will make it beyond the shores of Japan in future, but we certainly hope so — it's the most impressive device yet to duck out of the Android screen size arms race.