Many claim that Japanese sovereignty only terminated at that point.
The latest confrontation was set off last month, when a Japanese rightist organization repaired a lighthouse on one island as a sign of Japanese sovereignty.
The date for the return of Okinawa to Japanese sovereignty set for sometime in 1972.
After the Taiwan Expedition of 1874, the Japanese sovereignty of Ryukyu was confirmed.
Okinawa is returned to Japanese sovereignty, but US retains bases there.
However, these areas were under Japanese sovereignty until 1952.
Okinawa's reversion to Japanese sovereignty from US occupation in 1972.
It has been argued that acts committed against people subject to Japanese sovereignty cannot be considered "war crimes".
But Japan has demanded that Russia acknowledge Japanese sovereignty over all four islands before offering economic assistance or investment.
Japan has been demanding nothing less than full recognition of Japanese sovereignty over the islands.