When I came to Japan, I thought that Japanese students went to school all year with no breaks! Now that I've seen the calendar, I understand it a little better. I think Japanese and American students are in similar amount of classes. We have about two months of free time in the summer, but the rest of the year we're in school. Japan has an August and a March vacation, that's also two months! The big difference though? In America no one comes to school during vacations. Clubs and sports are usually all cancelled and most teachers take a break too. There is also very little school work. Most students don't study during summer vacation.
Of course, there are always exceptions. Some students still go to school for extra help or go to a special "summer school." There are also teachers who keep teaching in the summer and some sports activities keep practicing. Finally, more and more schools are giving students work and reading for the summer.
In America, our summer vacation actually started because students needed to go home and help their family. The summer was when everyone needed to work on the farm. Is this the same in Japan? March seems to be when many rice fields are planted. August seems to be a time when rice is harvested. I'm just guessing though, I might be wrong.
Most Americans don't work on farms anymore. Some people say that now we should go to school all year and take no vacation. I think the students would be really sad though. Summer vacation? No school? It's so much fun!