What an exciting time for you! Here is a thread that talks about the "great breeders"
http://www.yorkietalk.com/forums/bre...-breeders.html
Now that thread is really just mentioning all the "lines"/breeders who have made a reputation for themselves as valuable contributors to the Yorkie Breed.
Phrases such as "based on" or "descended from", can be just marketing terms and or ploys for potential buyers who know something about Yorkie lines to be reeled in for a sale. And it can be innocent as well. A way of communicating where their breeding stock is sourced.
There are a number of good articles in here on how to find a reputable breeder. They are found in our Library which is the second "blue" colored forum down when you go to the main menu.
I have a passion for health. And so, I will say to you, ask the breeders about what "specific" health tests they have done on their breeding pair, and what health concerns are in the lineage. Then I would check them out to see if they have posted the health tests on reputable health data sites;
Orthopedic Foundation for Animals, and CHIC.
Next of course or equal to is the temperament of the pair. Ideally you get to see both sire and dam. And then the temperament of the pups. Hopefully your breeder formally temperament tests the pups.
If you are going to pay premium dollars for a purebred then, you as the consumer should demand the very best health and structure and temperament of any pup you buy. The fact that you want a beloved PET, does not mean you should expect inferior health or quality.
It is very demanding to show a dog and it should be. Small flaws that do NOT affect the health or structure of a pup might make them in-eligible for the show ring. For example, eyes too light, or mismatched. Ears too large small and wrongly set on head. Coat likely to be either too light, too coarse, too soft, or a combination coat. Top line a "bit" and I stress a bit off. Likely to grow and weigh too large for the breed. Temperament off, too shy, too timid. And that one is a bit of a conundrum. All else being excellent you just might consider breeding this bitch or stud to an exuberant kind of over the top Yorkie. It would not guarantee the whole litter being of equal temperament - but...... some will and some may go to one end of the scale or the other.
And yes I am a show breeder; not of Yorkies though. But I believe that the public should demand "excellence" of their breeders.