1) City in Japan 2) City in Asia 3) City of Asia 4) City of Japan
Found on
https://www.crosswordclues.com/clue/oga
[Gojoseon] Ohga (오가, 五加) or Five Ministers was a political structure of Gojoseon and Buyeo. Literally, Ohga means five gas because Oh means five in Korean. Ohga were composed of Dotga, Gaeda, Soga, Malga and Shinga. Dotga is a minister of the eastern area, Gaega was a minister of the western area, Soga was a minster of southern area...
Found on
http://en.wikipedia.org/wiki/Oga_(Gojoseon)
No exact match found.
