Historical Rules · 1 May 2013
Rule 702.20j
Official source text from the 1 May 2013 Rules release
During the combat damage step, if an attacking creature is being blocked by a creature with banding, or by both a [quality] creature with "bands with other [quality]" and another [quality] creature, the defending player (rather than the active player) chooses how the attacking creature's damage is assigned. That player can divide that creature's combat damage as he or she chooses among any number of creatures blocking it. This is an exception to the procedure described in rule 510.1c.