Bitchu-Matsuyama castle

I'm wondering how much time I should allot for viewing the castle, not counting the walk up and back.

Thanks!

About 15-45 minutes for the honmaru.

The outer circles of defense are part of the approach and also take about 15-20 minutes to pass through one way from the nearest parking lot/bus stop (not including the main climb up from the base of the mountain).

You'll see the walls of the castle once you pass the parking lot/bus stop (as Uji mentioned). These are actually quite impressive on their own. I think the 15/20 minute estimate is good for the walk up, although you can certainly take more time if you are interested in photography or want to experience the castle slowly and appreciate it.

I'd probably give the honmaru more than 15 minutes. That would seem awfully rushed, especially if you are actually going to walk up from the station. I'd give it at least 30 minutes to read the information board, view the castle, enter it, exit it, walk around it, take in the atmosphere, and take pictures.

I guess in total from the parking lot area you can expect to spend around an hour there. Maybe a little more or less depending on your pace.