Hiking around Okayama, Hiroshima

Hey,

could you recommend some easy to reach hiking spots. I'm staying at Okayama and hiroshima.
I'm not looking for an overnight mountain stay. Just daily trips.
I'm not too much concerned about getting to a spot.
Getting back is my concern.
I want to make the most out of it and stay the whole day, reach the top of there is any.
So is like to stay to 18:00 maybe (mean being back by then at the base).
Often at that time trains and buses are already not in service anymore.

Any recommendations highly welcome! 😊

Thank you!

Seeing as nobody else is answering. . . I do more walking than hiking but I really enjoyed the walk/hike up to Bitchu Matsuyama Castle https://www.japan-guide.com/e/e5775.html You can visit Naoshima & wander around the Island & can do the Kibi plain with or without bicycles. The Okayama Prefectural website is a good place to start. https://www.okayama-japan.jp/en/
As for Hiroshima http://gethiroshima.com/hiking-in-hiroshima/

Hey, thanks for the suggestions.
Yeah, I guessI need to rent a car and go to mount daisen or/and iya valley.

Thanks Stan.
I ended up going to Ikura Cave very early in the morning. Then at 12:04 I moved back to Soja and took the bike ride from there through the Kibi Plains.
Still enough time to make it back before 18:00, when the bike rental closed.
Enjoyed the day much :) I had the 1.2 km cave for about 2 hours for myself! Awesome :D

Next day I rented the car and went to Mount Daisen. Bit of a long day but worth it much.

Glad you enjoyed yourself, always nice to hear.