The broad green park wrapped around Osaka Castle is more than just the castle's setting — it is one of the city's primary outdoor spaces for exercise, events, and seasonal celebrations. The inner moat and outer moat form concentric rings of water around the central keep, and the stone embankments between them are among the most impressive examples of early Edo-period engineering in Japan.
In spring the rows of cherry trees along the moat paths draw enormous crowds for hanami picnics. In autumn the gingko trees along the main approach turn a deep yellow. At any time of year, a circuit of the outer moat is a good way to see the castle from multiple angles and appreciate the scale of the fortifications without paying to enter the keep. The Osaka-jo Hall concert venue occupies part of the outer park.