Hi Mike, as a matter of fact, most of the winners are Japanese bred and/or kept kois anyways, especially the jumbos. But among the smaller Bu winners and runner-ups, we are getting to see more and more domestic kois. I am attaching hereunder the 50Bu champion, another Kohaku, bred by a Chinese breeder using momotaro parents.
My impression is that for all the past 7 China National Koi Shows, the organiser has always invited Japanese judges. I agree with you that at least among the koi lovers, the idea of borders has been blurred to a degree, or maybe because the people who choose to have this habbit, are, by nature, not the border-sensitive species, haha!