You have the previous owner fill out one of these. The previous owner fills in their personal information and membership number, and either stamps it with their personal 'seal' or signature.
Then you as the new owner fill out the rest of the card, and send it in to NIPPO along with 2000JPY and the original pedigree. And there you go. A few weeks later you'll receive the new pedigree in the mail. Just note here that you must be a NIPPO member to have a dog's NIPPO ownership transferred to you.
There were some great points made in the comments by @Éadaoin about NIPPO ownership and registration, so I'm editing it into this post.
Probably worth pointing out too that
a) You have to be the registered owner of a bitch to register her puppies in your kennel name with NIPPO
b) You have to be the registered owner of a stud dog to sign for his matings in NIPPO
c) A JKC export pedigree is not proof of ownership in NIPPO so you MUST get the stamped transfer card from the previous owner when you import a dog from Japan, otherwise no NIPPO puppies for your stud or brood, and
d) Don't rely on an import agent or translator to know (or to care about) these things at the point of sale. Be sure to ask for it. It may be very difficult to get back in contact with the previous owner once the dog has been exported, if you realise later on you need this done. I've seen people make this mistake again and again.