Samurai used family crests to identify themselves on the battlefields; at first, they were created to bring big samurai groups together and strengthen the local solidarity (As branch samurai families were given their own land, they took the name of their places and added modifications to the original design of their family crest to identify themselves.)
武家家紋は敵味方の識別や家示が目的とされるが、生じた当初は、大きな武士団をまとめ、結束力を高める為に生じたと考えられる（領地を分家に与え、分家は土地名を名乗り、そして家紋もアレンジする）。