The Tsujun Bridge (or Tsujunkyo) was constructed in the mid-1800s to bring water to the drought-prone rice paddies of the Shiraito Plain in southeastern Kumamoto Prefecture.
Today, the bridge still holds demonstrations of its unique water release system, designed to flush out the pipes of the aqueduct and prevent sand and silt from building up. The display can be seen on warm-weather weekends (generally May to the end of November) at noon, and lasts for 20-25 minutes. Make sure to catch the view of the spectacle both from the banks of the river and up on the bridge itself.
The Tsujunkyo area is also an excellent place to witness the rice harvest in action, with paddies glowing golden in the sun as the rice is cut, occasionally by hand as in decades past.