Senkoji Park seems to be the main attraction in the port town of Onomichi and draws many camera-toting domestic tourists. The park rests atop a mountain overlooking the city and provides panoramic views of the port, mountains and surrounding islands.
If you're lucky and happen to be up there on a blue-sky, sunshiny kind of day, then the view is definitely one you'll remember for a while. I gazed out at the mountains, which turned from a vivid green to a faded blue the further out to sea they were. Do check the weather forecast though, because if you're only planning on stopping in Onomichi for the day, Senkoji Park on a cloudy day could be rather boring.
That said, there are a few things at the park to keep you entertained for a while. First off there is the observation deck. Whilst being pretty small in size, does provide a great 360 degree views over Onomichi. The view is not only impressive, it is also serves to get your bearings if you find yourself a little disorientated after negotiating the maze of streets on the way up to the park. It's free to go up there and there is a small cafe/restaurant which you can enter through the spiral stairwell which leads up to the deck.
Just outside the observation tower there is a photographic display of the history of Senkoji Park. Even though the descriptions are all in Japanese, it's still interesting to see how the park has developed over the years. Right by the observation tower is the ropeway, another talked-up attraction in Onomichi. A single ride is only ¥280, with a round trip being ¥440. Whilst I much preferred walking up and down the trails along the mountain, taking the ropeway is a relatively cheap and easy way to get a quick visual overview of Onomichi. The tourist information center is right by the entrance to the ropeway at the bottom of the mountain. There is also a pretty decent waffle place right by there as well.
Back up on Senkoji Park there are a few other sights to check out. Of course, there is Senkoji Temple itself - The image of which is perhaps Onomichi's most iconic. There is also the Onomichi City Art Museum, seating pagodas, lots of green space to run wild, the 'Lovers' Sanctuary' (a small park with a red path in the shape of a love heart) and Petit Anon, a French style cafe with a glorious view and delicious ice-cream (beware the cafe's menu is only in Japanese, with a few little French words thrown in).
My favorite thing about Senkoji Park is without a doubt the collection of trails leading down the mountain. Starting near Petit Anon and winding down the hillside, you'll not only enjoy temples, shrines and burial sites but also with a quaint local neighborhood which will expose you to a less touristy side of Onomichi. In summer it can be a little tiring climbing up the trails but there are lots of shady places along the way to stop and catch your breath.
If you're passing through this area looking for something to do and the weather is behaving itself, pack a picnic lunch, take the ropeway up to Senkoji Park, enjoy the view and the afternoon breeze then, ice-cream in hand, wander down through the hillside trails. There are lots of little things to uncover in the many layers of Senkoji Park and you might find that it's these little things which are the most memorable parts of your trip.