"In a period of strategic uncertainty, both countries recognise the need to deepen security ties," Turnbull said. "Australia and Japan both seek an open and prosperous Indo-Pacific underpinned by the rule of law, where countries foster dialogue and co-operation and we all reap the benefits of economic integration and connectivity."
A "visiting forces agreement" has been in the pipeline between the two Pacific nations for years, and it is to finally be inked in late 2018. The agreement will set the legal status for the movement of military personnel, equipment and weapons between Australia and Japan.
This could allow Japanese forces to conduct military exercises on Australian soil — which will make it the first time Japanese soldiers will journey to the Land Down Under since Imperial Japan's bombing campaign against the Royal Australian Navy during World War II.
Turnbull's visit is to include a meeting with Japan's National Security Council as well as a trip to a Japanese Self Defense Forces base outside the city.
Australia and Japan's security interests have aligned closely in recent years, as they are both threatened by an emergent China. Chinese nuclear submarines were spotted around disputed islands between Japan and China in the East China Sea on Monday, while Turnbull criticized Chinese aid programs on Pacific Island countries as exploitative earlier in January.
They are also both concerned by North Korea, whose rapidly expanding nuclear program has captured the entire world's attention. Several of Pyongyang's missile tests in 2017 passed over Japanese territory and Canberra has championed the myriad sanctions levied against North Korea by the UN.
The last major item on the agenda is a discussion of plans to keep the Trans-Pacific Partnership trade deal alive. Japan has been the primary proponent of the TPP as a way of checking Beijing's mighty economy, and Australia, which though many times the size of Japan bears some economic similarities to its fellow island nation, has also become a strong ally of the agreement.
But shortly after being elected, US President Donald Trump pulled his country, the world's largest economy, out of it. Canadian Prime Minister Justin Trudeau has also expressed coolness towards the TPP, which could sink the agreement entirely.
At home, Turnbull's political opponents have opposed any deals with Japan until Tokyo puts a stop to their controversial whaling program. The two nations clashed over the program in the International Court of Justice in 2014, where Australia successfully acquired a condemnation of Japan's commercial whaling program in conservation zones.
Japan toned whaling down after that, but it has since resumed. Australian conservationist groups, as well as the politically influential Green Party, have roundly and frequently criticized the practice.