Nakatsu Castle is the main feature of the design on Nakatsu Citys draincover in Oita, Kyushu.
Considered on of the 3 great "water castles" that used river and sea as part of its defences. The other two being Imabari and Takamatsu.
The original was built in 1588 and was burned down in 1877 during the Seinan War, commonly called the Satsuma Rebellion.
The current concrete keep was built in 1964. No-one knew what the original keep looked like so it was modelled instead on Hagi castles keep.