The most important outcome of Prime Minister Turnbull's flash visit to Japan today probably won't be in what deals are signed or not (unless Turnbull is delivering bad news on the submarine tender). Rather, the most important outcome will be the hardest to judge from the outside: will Turnbull and Abe establish trust and a close working relationship?

Prime Minister Howard struck up a close relationship with prime ministers Koizumi and Abe (in Abe's first term in 2007), and the Australia-Japan relationship was elevated to a new, much higher level. Kevin Rudd was able to form such a relationship with South Korean President Lee Myung-bak and the bilateral relationship blossomed. Prime Minster Abbott developed close relationships with both Abe and Singaporean leader Lee Hsien Loong, and again both bilateral relationships were quickly elevated to new heights.

Good chemistry between leaders is key to both elevating bilateral relations and protecting them from tough divisive issues such as Japan's unwelcome return to whaling, something that will undoubtedly anger many in Australia and elsewhere. With both Abe and Turnbull in strong political positions facing weak opposition leaders, they could be at the peak of the Australia-Japan relationship for the coming years. It would be good for both countries if Turnbull is able to strike up as a good a relationship with Abe as his two Liberal prime ministerial predecessors did.