Cairns and Oyama signed a formal Sister City agreement on Monday, May 15, 2006.
Cairns and Oyama began friendships talks in 2002, when the Mayors of both Cairns and Oyama signed a Memorandum of Understanding. Since then, Oyama and Cairns have continued to strengthen their relationship and each year the two cities participate in a multitude of student exchanges programs. 
During Oyamafs first official delegation visit to Cairns, a group of local Oyama engineers and town planners accompanied the delegation to gain valuable insight into the local architectural designs of Cairns. With this information, they then returned to Oyama and designed the new Oyama International House Building (Omoigawa Michi no Eki), incorporating the typical Cairns architectural style into the building designs.
Benxi is a large industrial city located in Liaoning province in north east China. Benxi has a population of 1.571 million people and more than 20 ethnic groups exist together. The main industries are steel and coal, though 80% of the cityfs land is occupied by large forest mountains.
Mutual exchanges began between Oyama and Benxi in 1985, and in October 1994 the two cities signed a friendship agreement during the 40th anniversary ceremony of Oyama city. The friendship between Benxi and Oyama continued to grow for another 10 years, upon the two cities signing a Sister City agreement in 2004.