Japanese Chin Question

Our first Japanese chin was completely housebroken after 3 accidents. We recently adopted one from a rescue shelter and he is about 1 yr old. He has been more difficult to housebreak, but he is finally getting the idea. As for the weight, there are 2 kinds of chins, one is 7 lbs and under and the other, which both of ours are, are 10-14 lbs.

Usually Japanese Chins are easy to train. I breed them and all my puppies are using there papers are 5 weeks old and usually transition easily if taken outside often to potty out there. There are two weight classes up to 7 pounds and 7-14 pounds.