Post office will issue stamps according to different subject matter every year. In our country, generally the pattern has been designed by reflecting national features such as Chinese Zodiac, natural scenery and current news etc., in order to reflect the history, science and technology, economy and culture of a country or a region.
Panda is the rare animal in China. In order to promote exchanges and be friendly with other countries or promote panda, the ministry of postal had issued three sets of "panda stamp" in August 5, 1963 & January 15, 1973 & May 24, 1985. Two of these sets were designed based on the original painting by a famous painter Wu Zuoren. Panda’s life habits and characteristics were appeared lively and vividly.
If you think it from postal history, you’ll find lots of history from the letter pin ticket. Furthermore, in combination with the envelope, you can see the postal development and the change of the delivery time. So, it brings postal stamps collection value besides stamp itself.