The concept of joint development first appeared in international law in the 1970s. There are various definitions of joint development in the relevant legal literature. The British Institute of International and Comparative Law, having compared different definitions, defines joint development as an agreement between two States to develop so as to share jointly in agreed proportions by inter-State cooperation. As for joint development, in addition to the 2005 agreement, China reached a principled consensus with Japan in 2008 on joint development in the East China Sea. China has called for joint development in the South China Sea. Vietnam has concluded joint development agreements with Indonesia, Malaysia and Thailand, such as the Vietnam-Malaysia Agreement on the Joint Petroleum Exploitation. It is reported that Brunei and Malaysia have reached an agreement on joint development in the South China Sea.