Throughout 2014, there was increasing speculation that the "Sōryū" class (or a derivative) was the most likely candidate for the replacement. Defence technology sharing deals between Japan and Australia, along with the loosening of Japanese defence export restrictions, were seen as preliminary steps towards such a deal. The close personal relationship between the then-Australian Prime Minister Tony Abbott and Japanese Prime Minister Shinzō Abe was also cited as a factor in the likeliness of such a deal. In response to the rumours of the Japanese deal, unsolicited proposals were made by ThyssenKrupp Marine Systems (its Type 216 submarine concept), Saab (an enlarged version of the A26 submarine), and Thales and DCNS (a diesel-electric variant of the Barracuda-class submarine).