OSAKA, Japan – President Donald Trump arrived Thursday for the G-20 summit in the city known as "the kitchen" of Japan, but he's not here for the internationally renowned scorpion skewers or octopus balls.

Instead, he'll chew on some pretty tough global challenges: a trade war with China, military-style tensions with Iran, stalled nuclear talks with North Korea and whatever else might come up.

"We're going to be meeting with a lot of different countries, many of whom have been taking advantage of the United States, but not so much anymore," Trump said before leaving the White House on Wednesday.

Though Trump will attend G-20 summit sessions with leaders from around the world, most of the work will revolve around one-on-one meetings, including with Chinese President Xi Jinping and Russian President Vladimir Putin.

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Here's a sampler of what to expect:

China: Deal, no deal or more talk?

President Donald Trump and China President Xi Jinping

Trump will meet Saturday with Xi at what may be a make-or-break moment for a new trade agreement with China. Without it, the tariff-for-tariff trade war between the two countries could go on indefinitely, undercutting trade and growth in the world's two largest economies.

Trump, who threatened more tariffs if Xi does not make a deal, wants an agreement with China to end what he calls its unfair trade practices, including currency manipulation and theft of trade secrets.

China, which defended the way it does business, said Trump needs an agreement because China's retaliatory tariffs hurt American farmers and other groups of voters.

Few financial analysts expect Trump and Xi to sign and seal an agreement in Osaka. What's more likely: some sort of agreement to keep negotiating.

Claiming "we've been ripped off by everybody over the years," Trump said, "We'll see what happens with China, with Russia, with Japan, with many countries."

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Russia: Another round with Putin

Trump will meet Friday with Putin – one of the most scrutinized, and inscrutable, relationships in political history.

It will be their first sit-down since the release of special counsel Robert Mueller's report detailing efforts by Putin's government to interfere in the 2016 election to benefit Trump.

Trump, who noted that he approved sanctions on Russia for its misbehavior, denied allegations of Russian collusion with his campaign during the election.

He said it's important to "get along" with Russia because it can help on problems such as the civil war in Syria and aggression by Iran. He has been tight-lipped about the upcoming meeting – not saying whether he will bring up election interference or whether he'll warn Putin not to do it again in 2020.

"What I say to him is none of your business," he told reporters Wednesday.

Iran: A sanctions standoff

President Donald Trump holds up a signed executive order to increase sanctions on Iran, accompanied by Treasury Secretary Steve Mnuchin, left, and Vice President Mike Pence, in the Oval Office on June 24, 2019.

A week ago, Trump ordered a military strike on Iran for shooting down a U.S. drone – then suddenly changed his mind and imposed new economic sanctions instead.

Awaiting Iran's next move, Trump is trying to get other countries to keep sanctions on Iran and pressure it into a permanent commitment to give up nuclear weapons.

Tuesday, Trump threatened to use "overwhelming force" against Iran if it attacks U.S. assets or personnel, adding that "overwhelming will mean obliteration."

Leaders such as German Chancellor Angela Merkel – who is scheduled to speak with Trump at the G-20 – have criticized him for pulling out of a multinational agreement in which Iran agreed to give up the means to make nuclear weapons in exchange for sanctions relief.

North Korea: Beautiful letters with Kim

In this Feb. 28, 2019, file photo, U.S. President Donald Trump and North Korean leader Kim Jong Un take a walk after their first meeting at the Sofitel Legend Metropole Hanoi hotel, in Hanoi, Vietnam.

Trump will speak with Xi and Putin about efforts to revive negotiations between the United States and North Korea over ending the latter's nuclear weapons programs.

The talks stalled after the collapse of Trump's second summit with North Korean leader Kim Jong Un in February, though the president said he and Kim have exchanged "beautiful" letters in recent weeks.

After the G-20 summit ends Saturday, Trump will fly to Seoul for meetings with South Korean President Moon Jae-in.

Moon said this week that U.S. and North Korean officials are holding “behind-the-scenes talks” about a third summit between Trump and Kim.

"I'll be meeting with a lot of other people," Trump said. "But I may be speaking to him in a different form."

Saudi Arabia: Talk about Iran, not Khashoggi

US Secretary of State Mike Pompeo (R) is received by Saudi King Salman bin Abdulaziz at Al Salam Palace in the Red Sea city of Jeddah on June 24, 2019. - Pompeo traveled to meet with Saudi leaders today to build a "global coalition" against the Islamic Republic of Iran.

Trump is scheduled to have a "working breakfast" Saturday with Saudi Crown Prince Mohammed bin Salman – mostly to talk about Iran, not the murder of a journalist in which the Saudis have been implicated.

Agnes Callamard, a United Nations human rights expert, released a report last week alleging "credible evidence" that high-level officials in Saudi Arabia – including the crown prince, known as MBS – were involved in the death of Jamal Khashoggi, a Washington Post columnist.

The Saudis have repeatedly denied wrongdoing.

Presidential politics back in the USA

Trump will travel to the G-20 while Democrats take part in the first of a series of debates among its presidential candidates.

Trump began attacking the Democrats during his Air Force One ride to Osaka, tweeting that the first debate was "BORING!" He blasted NBC News for having technical difficulties during the broadcast.

Expect more political food fighting from Trump during the G-20 summit.

This article originally appeared on USA TODAY: Trump arrives in Japan for G-20. What to expect from meetings with China's Xi Jinping, Russia's Putin