The cat is a saint when there are no mice about.
More Japanese Proverbs:
A man with a sour face should not open a shop.Japanese
Don't take a golden sword to cut a radish.
Japanese
A man's good name is as precious to him as its skin is to a tiger.
Japanese
Luck is like having a rice dumpling fly into your mouth.
Japanese
If neither animal nor vegetable you be, then mineral you are.
Japanese
If you sit by the river long enough, you will see the body of your enemy float by.
Japanese