Seiko watches have a 6 or 7 character serial number on their casebacks. The second character can be a letter but the rest are all numbers. You can use the Seiko serial number in conjunction with the movement number to calculate the year of manufacture.

How do I know what Seiko watch I have?

Take the magnifying glass and scan the edges and back plate for an engraved series of letters and numbers. Write down the numbers for your reference. Look at the last four digits. The last four digits represent the model number of your Seiko watch.

How do I know what model Seiko 5 I have?

Seiko watches have a 6 or 7 character serial number on their casebacks. The second character can be a letter but the rest are all numbers. You can use the Seiko serial number in conjunction with the movement number to calculate the year of manufacture.