Odd question, that I can't find an answer for.

I'm looking several months ahead (I like to just get trips planned and not worry about it later) and all my preferred hotels for late April 2018 are showing "no availability" on every booking site, including their own.

The booking sites do turn up a smattering of hotels, but very few and nothing I'm interested in. My optimistic side says "just wait awhile", and my pessimistic side says "maybe they're really booked."

I suspect that the properties I'm looking at just haven't opened up those dates for reservations yet, is this typical for Japan? Most parts of the world we travel in open rooms for reservations many months in advance. What's typical in Japan?