Parque do Japão is the clearest public expression of Maringá's Japanese heritage. The park has formal gardens, water, and Japanese design touches, and it works well as a slow late-afternoon stop rather than a box to tick quickly.
The official visitor site lists the park at Rua Tulípa 987 and normally opens it from Tuesday to Sunday. It is south-west of the centre, so take a taxi or drive unless you are already nearby.