Sarah Hall

My breeder purchased a bitch (GSD) from Germany a few years ago, and when we were going through her paperwork (long story) we found she had a "C1" rating. I have no clue what this is, and cannot find it. The breeder called the person she purchased the dog from, and they said this was "the highest breeding rating" a bitch could get? She had a bad connection and couldn't ask WHAT it was.
Do any of you have a C1 rated dog, or can explain to me what this is and what it mean?

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"There is no hunting like the hunting of man and those that have hunted armed men and have liked it never care for anything else there after.." - Hemmingway