Table etiquette is a very complicated thing especially in such a country like Japan where, I must say, there is food worship. But do not be afraid because Japanese behavior at the table is not as complicated as it may seem at first glance. Japanese rules of conduct at the table have significantly changed for the last one hundred and fifty years. And it surely can be asserted that not any Japanese could behave in accordance with all Japanese traditions. But if you stick to simple rules described below Japanese will treat you more benevolently.
Despite the fact that Japan is a modern and highly-developed country which has borrowed and adopted many aspects of the West, it still has tremendous and influential views on social behavior. Even now politeness and reticence in Japanese behavior are the fundamental elements of etiquette. Of course it is sometimes difficult for a foreigner (or gaijin as Japanese call it) to adapt to Japanese customs and behavioral patterns but Japanese themselves do not expect gaijin to follow Japanese behavioral model precisely. In this respect Japanese are quite tolerant to gaijins and allow foreigners to behave in a way which will never be acceptable for themselves. However one should not abuse such tolerance: it is good just to observe simple universal rules of conduct accepted in your own country.