I think I know what you meant, but you mixed stones in the beginning of your post. The Chinese 12k is a different stone than the Belgian Coticule.

The 12k is a finer and also a slower polishing stone than a coticule. 50-100 passes is not uncommon. I usually do 50 and then test shave and go back for more passes if the edge needs it.

I hope that helps.

Chris L