China and Vietnam have had a constructive approach towards their territorial disputes since restoring relations in 1991. Regular high-level talks and agreements have gone a long way to calming rifts. For all the effort, though, bouts of tension, particularly over the South China Sea, have ensured that the regional instability that was at its height with a brief land war 29 years ago has remained. Deals struck at the weekend to make a concerted push towards resolution through economic co-operation are therefore to be applauded. Their pledge to turn border areas into economic zones, jointly explore reputedly oil-rich seabeds and work together on issues including oceanic research and environmental protection is a step in the right direction. The pact signed in Beijing during Prime Minister Nguyen Tan Dung's visit was short on specifics. It did not tackle the contentious issues of the Spratly Islands, also claimed by Taiwan, Brunei, Malaysia and the Philippines, and the Paracel Islands, occupied by China since 1974. Such moves are essential in building confidence between countries with the potential to be antagonists. The lure of oil and gas to help fuel the Chinese and Vietnamese economies has time and again created suspicion and animosity. China three months ago told Exxon Mobil to pull out of an oil exploration deal with Vietnam that it contended was a breach of sovereignty; a brief naval battle near one of the Spratly reefs in 1988 left 70 Vietnamese dead and brought the sides close to full-scale conflict. Dialogue and co-operation will foster the understanding necessary to maintain stability. Fleshing out the agreements in a timely manner is the next move. Demarcation of the land border, a project started in 2002, should be completed before the year is out. Extending the work to offshore waters will reduce the potential for conflict. But it is through deeper economic co-operation that the best chance for a lasting peace lies. Ensuring that plans for industrial zones go ahead is essential. Pushing on with joint infrastructure work and petroleum exploration will build trust. Only through understanding can the seemingly intractable sovereignty issues be resolutely tackled.