In fact, the purpose of doing this is nothing more than to verify the annoying identity. If we get them to sign, it's over. Most people can't read, so they can only press their fingerprints. As for how to distinguish, there was no high technology at that time, and it could only be recognized by the naked eye.

Signature and drawing are two ways, or drawing is more popular, simple and practical. There was no high-tech fingerprint identification in ancient times, but careful observation shows that the fingerprint morphology of two different people is still very different. You can also take a fingerprint with your family and compare it. If you look closely, it's really different. In ancient times, there were not many people living in an area, and no one wanted to use fingerprints. Therefore, the method of withdrawing troops is still a very desirable form.

China can be said to be the birthplace of fingerprints. There were clearly visible fingerprints in the Stone Age. Later unearthed cultural relics also have many cultural relics with fingerprints. Fingerprints will also be applied to contract documents, which are still used to solve crimes. The earliest should be invented by Song Ci, a criminal officer in the Song Dynasty. In his works, a large number of related documents about fingerprints are recorded.

After the Song Dynasty, fingerprint technology began to progress and developed slowly. Song Ci compared and observed many fingerprints, and finally came to the conclusion that people's fingerprints are different and will not change all their lives. Even if they are pressed many times, the fingerprints are in this shape. Unless the finger is injured or incomplete, it will be different.

But fingerprints also have a deterrent effect to some extent. China people believe that "there is a god who holds his head three feet high". Therefore, fingerprinting is the testimony of heaven and earth, and doing bad things will be rewarded.