Sony Xperia Z4 has finally landed in Japan. Not that it's expected to be anywhere else but the Japan-exclusive phone is finally available courtesy of NTT DoCoMo. The carrier has released the smartphone Sony Xperia Z4 (SO-03G) so the Japanese consumers can now order online or pick up the phone in stores. It's the same Xperia Z3+ introduced to the rest of the world. There's no key difference except for some improvements in software.