The Kashima Gatalympics turn the Ariake Sea mudflats into a sporting mess, with participants racing, slipping, and falling through the tidal mud near Hama. It is funny, local, and very specific to this coast, where the sea pulls far back and leaves an enormous grey playing field behind.
The event is seasonal, usually held in late spring. If your dates line up, it gives Kashima a reason to feel lively rather than merely pretty.