Arriving early at accommodation?

I'm making my itinerary now and most of my distances require at most 3 hours travelling. I'm an early bird (I don't mind getting up at 6 or 7 am) so that means that in almost all places I like to visit I will arrive at 11-12 am, much too early to get a room. But is it possible that I can drop of my luggage at at most minshukus/ ryokans/ hostels before the official arriving time? If not, what else are my options? I will carry a large backpack, too large most of the time for a coin locker at a railway station.

...you can! Usually the check-in time in ryokans is 3pm but if you mention in your reservation form that you'll arrive at 11 or 12, they'll do their best to get your room ready by this time. I always stay in ryokans and it was only once that I came at 11am and they needed some time to get my room ready. It was ready at 1pm then. Enjoy your stay!

Thanks for your answer, but without reservation? If I make a sameday reservation eg at the tourist office or just drop by? I hardly ever make reservations because my itinerary changes many times. I always have an idea about my route but exact dates do change too often.

I usually make my sameday reservations at Welcome Inn Reservation Center and I can only recommend them further. No troubles experienced so far. Please check their webpage at
http://www.itcj.jp

I think you can expect you'll be allowed to leave your baggages at your hotel/ryokan/hostel even if your room is not ready.

As to the reservation, please find further information.

Thanks for the answers and the link, I bookmarked it.