Kokura Castle sits on the Murasaki River at the edge of the arcade district, its white-walled donjon visible from much of the city centre. The original was the seat of the Ogasawara clan; the current reinforced-concrete reconstruction dates from 1959 and houses a museum of castle-town life and a small theatre.
The surrounding gardens are the best part. The castle park is free to enter and full of cherry trees in spring, with the moat reflecting the keep and Riverwalk Kitakyushu rising on the far bank — an unusual collision of Edo-period stonework and shopping-mall postmodernism. The Japanese garden next to the castle is worth the small extra entry fee.