Japan (Tokyo) School Holiday 2015

I know it's still early but we plan to visit Tokyo in Spring 2015, and our main purpose is to see the beautiful Sakura there. But we also know that it is school holiday at the same time, so is anyone know exactly when is the school holiday in Tokyo, 2015 ?
well, we see that usually between end of March to early April, but because we also don't want to miss Sakura, precise date will be helpful, thanks.

It is never too early to plan a vacation!!

Dates are not fixed.
They never have been, and with global warming and what not, the dates are more varied. Take the first 2 weeks of april as the best bet to see something. It might not be the peak, but there would still be sakura.

Unfortunately, these first 2 weeks are also the vacation period of kids.

The Spring break is normally between 26 March and 5 April in Tokyo for public(state) schools. Private schools run different but similar schedule.