I strongly suggest a visit to Miyajima Island alongside Hiroshima when visiting this part of Japan and 2 days is a perfect amount of time to experience both places.
Miyajima Island – 10 Best Experiences not to miss
Explore Miyajima Island with the infamous floating torii gate of Itsukushima Shrine. Hike the mountains and witness the fire that has been burning for 1200 years in Mt Misen. A detailed travel guide on what to see and do including hiking options.