A few minutes' walk from Odawara Castle, Seiganji is one of many Buddhist temples clustered around the eastern districts of the town. It's a charming, intimate little place, with a handsome worship hall that's home to some unusual but cute wooden carvings of chunky fish, swimming towards each other on a beam under the eaves.
From here it's also just a couple of minutes to Hoanji, a more modern temple with an interesting population of statues and carvings.