Sesshoumaru knew he needed to return to his father's Shiro to take his rightful place as Lord, but he stopped on the way with one of his sires vassals.
The old magnolia tree was set deep in the forest next to his father's, no, his Shiro. Bokuseno was knowledgeable about many of the affairs of the West and would need to be consulted.
Upon arriving, he realized that his trip to tell the vassal of his father's demise was unnecessary, as hanging from the bark of the tree was the Tensaiga.
The useless Sword of Heaven seemed to mock him from its hanging place.