What you should have been given
When you buy a registered puppy the breeder should hand you a JKC registration card carrying the dog’s registered name, its registration number, its date of birth, its breed and colour, and the registered names of its sire and dam. The transfer section on the back should be signed by the breeder.
If you were given a photocopy, a scan, a certificate from an organisation you have never heard of, or a promise that the papers will follow, you have not been given a registration.
Check it against the register
Take the registration number and the date of birth from the card and check them against the club’s own records. Both must match. If someone has copied a real number onto a card for a different dog — which is the usual way this is done — the date of birth is what gives it away.
Worth knowing
Do it before you pay, not after. A breeder with nothing to hide will wait the thirty seconds.
If nothing matches
The online register is complete from a published date. A number older than that may belong to a genuine dog whose record is still in the paper ledgers, and the search will tell you so rather than calling the dog a fake. Send the number to the office and the ledger will be checked.
If the number is within the online coverage and nothing matches, that is worth reporting. The club would rather hear about it.