Groups across the political spectrum still have to overcome many obstacles before they can join forces in future anti-Japanese campaigns, political commentator Johnny Lau Yui-siu warned yesterday. At yesterday's City Forum, legislator Chan Yuen-han said last night's rally was the beginning of co-operation between groups with different political leanings. 'These kind of [anti-Japanese] activities are not election campaigns. We have to co-operate on the basis of our common goals and we should set aside our other differences,' she said. However, Mr Lau said he believed there was only a 50-50 chance that the groups would continue to join forces in campaigns against what they see as Japan's revived militarism.