The shell came from his teacher. Palm-sized, the pattern on the back worn glossy, a small piece chipped off one edge.
Two rules: do not let anyone else shake it, and do not set it down upside down.
He kept the first for thirty years. The second he broke once — he put it down face-down after a casting and went to answer the phone, and only remembered when he came back.
From that day the shaking made one more sound.
It had been three, and then the fall. Now it was four.
He tipped it out and counted. Nothing extra. He turned the shell over and held it to the light. Empty.
He shook it again. Still four.
He held it to his ear, shut his eyes and shook it for half an hour, counting.
The fourth is lighter than the other three and duller, and it comes earlier — in the instant before his wrist has started to move.
He found a fine-toothed saw and cut round the rim.
The shell is double. The middle layer was added later, and he knows the join; it is his teacher's work.
Set into the cavity is a thin piece of bone, ground flat, the size of a fingernail. Six horizontal marks are cut into it, three solid and three broken, reading from the bottom up.
He looked it up. It is Gu.