So instead of being able to isolate some actual thief, they could just rule out a family member performing the actual theft. It helped that there was more to go on in terms of what clues might be around--paper where it shouldn't be or some measure of misplaced damage--but any actual indications as to who might have made off with the vase...

The "how" answered itself when it came to escaping with what was doubtless a rather cumbersome item: take the exact same way of removing it that had been chosen with the wall. Or keep reapplying the same trick in reverse. Nevertheless, along with Toshiko, Ryuuko wished to see the scene of the crime rather than the approach to it.

"Daidouji-san, was the case protected against being displaced in some manner? It seems unlikely to me that your defences were constructed to be defeated by a single skill."