There is no such thing as a perfectly trained chin

As any reputable dog trainer or book will tell you, canine learning comes from repetition. When a behavior is repeated often enough, dogs develop habits, or conditioned responses.  Assuming those habits are positive ones, such as eliminating outside, coming when called, lying down and staying when told, and others - you will have what you want: a trained Japanese chin. That's because all dogs are creatures of habit. Once you set up a routine of signals and conditioned responses, your dog will do exactly what you tell him every time. Right? Not exactly...

No trained response is infallible. Creatures with advanced brains can think - and they can also make mistakes. Think about two of your own conditioned responses. When the telephone rings you have a habit of answering it, but one day you decide not to take any calls. The telephone rings but you decide not to take any calls. The phone rings but you keep reading your book. You know what you normally do, but today you decide not to do it. You also have a habit of stopping at stop signs. But one day you are tired and distracted and you roll through an intersection. Even the most experienced drivers make mistakes.

Similarly, there will be times when even the best-trained dog will either defy training or make a mistake. So it is in everybody's best interest that you avoid becoming complacent or over confident about learned behavior. Do not rely on conditioned responses in potentially dangerous situations. For example, you should never unleash even the best-trained chin near a busy road. One mistake could result in injury or death to your beloved pet.

All dog owners need to reinforce their pet's conditioned responses. Certainly the more practice and proofing you do with you dog, the more reliable his response will be. Skilled human beings, from tennis pros to typists, need practice to stay in top form. This is because all learned skills need reinforcement.

When you feel you have achieved a well-trained dog, continue to practice obedience exercises once in a while. It can be fun for you and the dog and it reinforces the good behaviors you worked so hard to achieve.