The supply of crude oil to Japan from China's huge Daqing oil field has been halted since January and is unlikely to resume due to increasing demand for energy in China.

The oil field's reduced export capacity, along with China's price demands, have also made it almost impossible to resume the supply of oil to Japan, sources have said.

The supply began after the 1972 normalization of relations between the two countries. It has been a symbol of bilateral friendship ever since.