The rules for generating passport numbers in different countries and regions vary, and usually contain elements such as country code, issuance information, and verification code. The following are examples of passport numbers and brief rules for some common countries： --- ###**Chinese passport** -**Example**: E12345678 (ordinary electronic passport) or G12345678 (old version of ordinary passport) -**Rules**： -**The first letter **: Indicates the passport type： -**E**: Ordinary electronic passport (new version after 2012). -**G**: The old version of the ordinary passport (has been phased out). -**D**: Diplomatic passport. -**S**: Official passport. -**Subsequent characters**: 8 digits, including issuance information (such as area code, year of issuance, etc.) and serial number. -**Check code**: The last digit may be generated by a specific algorithm (such as modulo 10 or modulo 11) to verify the validity of the number. --- ###**U.S. passport** -**Example**: 123456789 -**Rules**： -**All numbers**: 9 pure numbers, no letters. -**Generation method**: Randomly assigned by the system, there are no public coding rules, but it contains an internal verification mechanism. --- ###**British passport** -**Example**: AB1234567 -**Rules**： -**The first two letters**: represent the passport type or issuing agency. -**Subsequent 7 digits**: Randomly generated serial number, the last digit may be the check code. --- ###**Japanese passport** -**Example**: TR1234567 -**Rules**： -**The first two letters**: fixed as “TR” (ordinary passport) or “PD” (diplomatic passport). -**Subsequent 7 digits**: sequence number, including check code. --- ###**General rule features** 1. **Uniqueness**: Each number corresponds to a unique holder to avoid duplication. 2. **Check code**: Usually modulo 10, modulo 11 or ISO 7064 algorithms are used to prevent input errors. 3. **Country code**: Some countries will include nationality information (such as the letter prefix of the Chinese passport) in the number. --- ###**Precautions** -**Privacy protection**: Passport numbers are sensitive information and should not be disclosed or shared. -**Dynamic changes**: The rules of various countries may be adjusted, subject to official agencies (such as the Immigration Administration) for details. -**Legality**: It is illegal to forge or improperly use a passport number. If you need to learn more about the rules of a country, it is recommended to consult the country's embassy or consulate or the official immigration department directly.