>>100215598I looked at the panels very closely. I might be wrong, but... While Tomoe and Usagi were approaching the small ceremony house, the tied stone wasn't depicted. One of them had to place it previous to both entering.
If Tomoe had placed the stone, Usagi would have witnessed the act and it would have been a strike against the moment and the respect for the tea ceremony that was to come.
If Usagi placed the stone on the path after Tomoe had entered, just prior to his own entry to the small house, he would have gotten away with it.
So... It's my theory that the tied stone was Usagi's small token of his decision to keep things as they are with Tomoe and their friendship. Likewise, Tomoe expresses longevity and purity in return to Usagi in how she sees him.
I might be reading into it too deeply, but I suspect Stan knew what he was doing. Fucking Karma is so harsh. In a moment of weakness, Usagi could have rolled the dice and declared his love, and it probably would have worked - except for one thing. Tomoe helped raise a young lord that will always be surrounded by enemies. Always.
Even if her station in life were changed by marriage or reassignment, that duty would remain hers within her heart. Goddamn.