The first Navigation Day was celebrated on July 11, 1955, a date which was also the 550th anniversary of Cheng Ho's first voyage of his seven oceanic expeditions made during the Ming dynasty to the South Pacific and along the Indian Ocean coasts. The 10th Navigation Day was on July 11, 1964. To mark this memorial occasion, a set of commemorative postage stamps was issued. The design contrasts an ancient 〝treasure ship〞used during Cheng Ho's oceanic expeditions with a modern liner, showing our early achievement in navigation history and the importance of development of our modern navigation enterprise.