Korakuen, Okayama: Beautiful Photos from one of Japan's Top Three Gardens
There are several museums located in the vicinity of Okayama Castle and Korakuen Garden. I didn't visit any of these, but fans of art or looking for a bit of a history lesson might find something of interest here. (I would like to check out a couple of them at some point,) This is Japan Guide's list of Okayama museums with important details.
Korakuen Garden is just across the river from Okayama Castle. Walk about 30 minutes straight east from Okayama Station, or take a 5-minute tram ride to Shiroshita, from where the garden and castle are an additional 10-15 minute walk. The closest entrance to the pedestrian bridge is the smaller south gate (seen in the first photo above) to the right, but the main gate is a short walk to the left after crossing the bridge. The Prefectural Museum is located beside the main gate.
The garden is open 7:30-18:00 from March 20 through September and 8:00-17:00 other times. Admission is 400 yen, but most people will want the combo ticket for 560 that includes Okayama Castle (not available when the castle has special exhibitions).