Ushio Naval Experimental Station Site

Ushio was built in 1945 as a dispersal site for the Navy's Shimada experimental station. Its river-facing position was intended for microwave experiments connected with the Z research programme. That programme investigated high-power electromagnetic radiation as a possible weapon against aircraft; its ambitions should not be confused with an operational weapon. Ushio was still unfinished when Japan surrendered.

The remains included foundations for an oscillator room, power room and parabolic-reflector supports. Municipal excavation in 2013–14 documented the structures and recovered insulators, wire and metal fittings. These physical traces illuminate the electrical infrastructure behind wartime research, complementing the surviving Navy records discussed in the report's history-of-science appendix.

River widening subsequently removed the main reflector supports and the oscillator and power-room remains. A municipal account published in 2015 recorded transformer-room and coal-gas facility remains outside the construction area on private land. That dated account does not establish their present condition or public accessibility.

The approximate marker uses the excavation report's world-geodetic-system coordinate for the former site. It identifies the historical research location, not a surviving reflector or a visitor entrance. This is not an intact laboratory museum, and access to remaining private plots has not been verified. The municipal report is the most useful starting point for understanding the now-altered landscape.