Visited in winter. It's a really nice and quiet park, we had a lot of fun in the snow. We even saw squirrels in the trees. And for other foreigners - restrooms are closed over winter! Don't be caught out, there are nearby ones in convenience stores instead.
Loved the trees and the colors here in autumn! Was here in Oct, and the autumn colors were just coming out. Stark difference from the pink sakura flowers in spring, red leaves, or just bald trees gives quite a big contrast