Here are some issues that the leaders could discuss at their summit on Friday:

- Security commitments -

Ishiba said in a recent speech that Tokyo must "continue to secure the US commitment to the region, to avoid a power vacuum leading to regional instability".

He said he hoped to agree with Trump that Japan and the United States regard their alliance -- along with other security networks such as the "Quad" with India and Australia -- as "essential to strengthen the free and open Indo-Pacific".

His comments underscored jitters over China's military build-up and Trump's "America First" agenda, which may include demanding Japan shoulder a greater proportion of defence costs.

Around 54,000 US military personnel are stationed in Japan, mostly in the Okinawa region east of Taiwan.

- Disputed islets -

At past Japan-US summits, the leaders confirmed that a disputed chain of tiny uninhabited islands claimed by Beijing but administered by Tokyo, known as the Senkaku in Japan and Diaoyu in China, is covered by the Japan-US security treaty.

Ishiba told parliament this week that it was "important" to reaffirm this with Trump -- a move that could rile China.

Japanese media said Trump and Ishiba will likely also reaffirm the importance of peace and stability in the Taiwan Strait, echoing previous joint statements between the countries.

- Trade and investment -

Trump's predecessor Joe Biden blocked a $14.9 billion bid by Nippon Steel to buy US Steel last month citing national security concerns, a highly unusual move that irked Tokyo.

Japanese businesses are also wary after Trump moved to impose tariffs on major US trading partners Mexico, Canada and China, although the levies on Canada and Mexico have been postponed.

Ishiba is expected to tell Trump that Japan's massive investments -- the country is the largest foreign investor in the United States, and vice versa -- help create jobs.

Japan's Nikkei business daily reported that the two leaders' joint statement will mention the importance of a global trade system based on "free and fair economic rules" as well as promoting an investment-friendly environment.

- Energy and technology -

Trump and Ishiba's statement will also mention cooperation in the fields of energy and cutting-edge technologies, the Nikkei said.

One major new tech project has already been announced: the Stargate drive to invest up to $500 billion in AI infrastructure in the United States, led by Japanese investment behemoth SoftBank Group and US firm OpenAI.

Ishiba will propose increasing imports of natural gas from the United States, chiming with Trump's plan to "drill, baby, drill", while boosting energy security for resource-poor Japan.

Although Japan aims to make renewables its top power source by 2040, it remains heavily dependent on imported fossil fuels and has the dirtiest energy mix in the G7, campaigners say.

- 'Golden age' of ties -

Trump and Ishida's joint statement could also pledge to build a "golden age" of bilateral relations and bring the Japan-US alliance to "new heights", the Nikkei reported.

This is language already familiar to Trump, who vowed after taking office in January that "the golden age of America begins right now".

But some have questioned whether the bookish, detail-oriented Ishiba can replicate the close relationship enjoyed by Trump and former prime minister Shinzo Abe, who was assassinated in 2022.