traveling to japan 2016

hello,
so I was planning to visit japan for three month in April 2016 until June 2016,
however when I try to book a reservation for hotels in booking.com I get the phrase "no room available for this date" now my question is,
does that mean its to early to book reservation a year in advanced or the hotels are actually already booked a year from now,
did that happened to anybody?
I'm really frustrated because I really want to go to japan next spring but all the cheap hotels say the same thing.....please help
*note - I did try to contact booking but no one answered

Most hotels only book a few months in advance so you'll need to contact them directly to book this far in advance.

Oh thank god!! Thank you so much!!
But how should I contact them? Through booking.com? Via emails?
Should I write in japanese or English?
Do you know if Ithere is an agency that I can trust that can book my ideal reservations?
Thanks again ;)

If the hotel has an English page, you can most likely try emailing them in English.

You can also check out: http://www.japanican.com/en/