I'm wondering if there are luggage storage lockers suitable for your standard 9x16x22 inch luggage either at the train station, at the bus station, or at perhaps a youth hostel near the Hiroshima Peace Park. We'd like to try the new Bus Pass offered by Willer Express to travel on the overnight bus from Tokyo to Hiroshima, but would then have our luggage with us for the day in Hiroshima before continuing to Kyoto to begin our stay there.

There is luggage storage at Hiroshima, at the railway station, you need small coins for this (we also used the storage here & helped a Japanese lady who didn't have enough coins). The question has been asked before on this forum, see http://www.fodors.com/community/asia...-hiroshima.cfm
with lots of useful information. I would guess the Youth Hostel would also keep the luggage for you whilst you look around that day.

You will need extra large lockers, but unfortunately there aren't many of those and are usually in use. Your best bet is to head for the South Exit, where there are more larger sizes.
There are also some commercial left luggage offices in front of the station building.

Thank you for the information about the South Exit. I apologize for re-asking a previously answered question. I fear in the piles and piles of research I have done, I simply forgot.

Thanks for the link!