The great 16th Century sword master Tsukahara Bokuden had three adopted children. To test their fencing skills, he propped a wooden block pillow above the sliding screen that opened into his quarters and invited each of his sons to visit in turn.
The youngest son came first. As he opened the door, the pillow fell. This son dodged the pillow, drew and struck it before it hit the floor.
The second son saw the falling pillow and caught it.
The third son, sensing something wrong at the entrance to Bokuden’s room, without going in, reached up and removed the pillow first, then entered.