Why are there three stamps on a stamp?

1. Stamping can prevent stamps from being reused and ensure the validity of postage.

2. The role of commemoration and collection. Postmark is a stamp stamped by the postal department to indicate the cancellation of postage certificate, which is used to indicate the delivery date of mail and the name of post office. The style and stamp position of postmark will be specially designed according to special festivals or events, which has high artistic and commemorative value.

3. The paper quality and printing technology of stamps are different in different years and regions. In order to ensure that mail can pass the inspection and sorting of postal departments smoothly, stamps must meet relevant regulations and standards. Therefore, stamping stamps can also play the role of anti-counterfeiting and identification, helping postal departments to manage and sort.