When groups of yarns are interlaced and a braid is being formed, the center of the braided structure represents the point of braiding (POB). The Point of Braiding, also know in Japanese as the Kensaki, is where the interlacement occurs and the structure becomes visible.
The point of braiding provides a great deal of information to the braider: it can tell whether the completed sequence of interlacements has been executed correctly, and whether the tension (determined by the visible length of the thread floats) is correct.
When the point of braiding is not visible, other visual cues must be used to determine whether the sequence of interlacements was executed correctly — such the exterior appearance of the braid.