My family and I occasionally eat at a Japanese food family restaurant chain called Yumean (夢案), which we all enjoy. I took this picture last month, but at the time we were all surprised and amused to see that the size of this child's plate had shrunk quite a bit. Since that time, we have noticed the same thing a many other restaurants - often in the form a new menu. Hoping you will not notice, I am sure. Because of rising prices and possibly also due to smaller or unsatisfactory new menu items, it is easy to see that restaurants are not as crowded as they were only several months ago.
Reduced serving sizes are especially interesting to foreigners, because we typically laughed a small serving sizes before the current food crisis. I have generally assumed that Japanese serving sizes are about half of what they are in the US. This does not leave you very much room to cut further. Small serving sizes are undoubtedly more healthy than the huge platters you receive in the US, but at some point even Japanese are going to be left hungry.