There's no actual castle there, not even a reproduction. But it's a historically important place as the location where Ieyasu Tokugawa retired after being the first shogun. Now it's a peaceful park in the middle of the city.
Nice walking area with several paths, a nice garden, and two historical museums. Though the museums are 95% japanese text as of April 2024.
There's also a nice 30 minute boat ride around the moat for 1000¥. The boat tour guide only speaks in Japanese as well but that's okay, you can focus on taking pictures. Note at the end of the ride the roof is lowered and you have to bend down while you go under the low bridge. One tip, board on the left side of the boat which means you'll be on the right side while going around the park. It has a better view for pictures most of the ride.
The front architecture of Sumpu Park is absolutely stunning.
Inside, the park is spacious and very comfortable, making it a perfect spot to sit back and relax. A great place to unwind.
