Hirano Old City is a rare surviving pocket of older Osaka: a medieval moated town rebuilt in the early Edo period on an orderly street grid. Most of the moats have disappeared, but the district still keeps a quieter historical feel, with traditional machiya, temples, shrines, and narrow lanes.
Come for a slow walk rather than a single monument. It is most rewarding if you like seeing how older urban fabric survives inside a much larger modern city.