Naha: why all booked on Saturdays?

Why are the hotels in Naha all booked on Saturdays in August and September?

Not sure if I should keep checking for availability at Toyoko Inn or just book at another hotel all together.

Is there another chain you can recommend similar to cheaply but clean Toyoko Inn?

August and September are peak times, and because cancelling the Toyoko Inn is free, many people book even if their plans aren't 100% since they can cancel before easily. If you're wanting Toyoko Inn specifically, 2 pieces of advice. First, use the Japanese site and make sure to check the "Toyoko Inn Members Calendar". Those rooms are updated first. Next, refresh, refresh, refresh! Something will pop up, even if its not a room you particularly like. It might take you some time to finally find a room free, but one usually always pops up for me. I've even gotten Toyoko Inn rooms last minute for super popular festivals, so it happens.

If you're not the type to be flexible and want your room booked now, then yeah, maybe using a different hotel chain is better. I think the Route Inn hotels are all over... you could see if there are any available for your dates.

Thanks scarreddragon.
Your answer makes a lot of sense.
Let's hope smthg pops up for me.