TOKYO -- A study of the history of relations between China and Japan has ended because of different ideas on how to approach the project, a report says.

Japanese participants in the study said Tuesday the joint project was ending because both nations were unable to reconcile their positions on how to approach the study of international relations in Asia, the Japan Times reported.

Time constraints also played a significant part in the decision, involved historians said.

"We have never thought of (co-writing a single history) given the time frame. It's impossible," University of Tokyo professor Shinichi Kitaoka said.

The head of Japan's team added that historians from both nations will now write their own versions of past events and compare versions once completed.