The visual jutsu bloodline trait (Dojutsu & Kekkei-Genkai) belonging to the Hyuuga clan. Byakugan means the all seeing white eye. It has almost 360' vision and is very useful for very long distances. Though not as serious as the Sharingan and Mangekyou Sharingan, overusing the Byakugan can effect the users eyesight. More information about it can be found here.