Himeji is situaded just one hour and a half from Osaka by train which makes it an obligated visit. The main attraction is undoubtedly the Himeji Castle (姫路城) which is the largest one in Japan.
It is as well the most visited castle in the country so you should expected huge queues to get inside (don’t trust the pics!).
Is impossible not to find it as you can see as soon as you leave the train station. Next to the castle you can visit the Himeji Park which it’s worth a visit.
No need to wake up really early for this day trip, give a walk around the castle to get a good spot to see the sunset and you can get a train and have dinner in Osaka in no time.
All pics here