Always fearful of rebellion, the Qin Emperor devised a system to ensure that troops could be moved only by his express order. He had tokens, fu, made consisting of two interlocking parts. One half went to the commanding officer, and the other half stayed with the Emperor. An order by the Emperor to move troops would be brought by a messenger carrying the Emperor's half token. When the commander ascertained that the two halves fit, the order was valid. This token, in the form of a tiger, is inscribed in gold lettering: "Token for moving soldiers, the right half is in the Emperor's hands, the left at Yangling."