Trump, after call with China’s Xi, told Japan to lower the volume on Taiwan

Days after Japanese Prime Minister Sanae Takaichi outraged China by suggesting a Chinese attack on Taiwan could mobilize a Tokyo military response, Xi spent half of an hourlong phone call with Trump, people briefed on the matter said, hammering home China’s historic claim to the democratic self-governing island as well as Washington and Beijing’s joint responsibility to manage the world order.

Later the same day, Trump set up a call with Takaichi and advised her not to provoke Beijing on the question of Taiwan’s sovereignty, said Japanese officials and an American briefed on the call. The advice from Trump was subtle and he didn’t pressure Takaichi to walk back her comments, those briefed on the calls said.

The Japanese officials said the message was worrying: the president didn’t want friction over Taiwan to endanger a detente reached last month with Xi, which includes a promise to buy more agricultural products from American farmers hit hard by the trade war.

Asked about the exchange with Takaichi, the White House issued a statement from Trump to The Wall Street Journal: “The United States relationship with China is very good, and that’s also very good for Japan, who is our dear and close ally. Getting along with China is a great thing for China and the U.S. In my opinion, President Xi will be substantially upping his purchase of soybean and other farm products, and anything good for our farmers is good for me."

“We signed wonderful trade deals with Japan, China, South Korea, and many other nations, and the world is at peace," Trump added. “Let’s keep it that way!"

The Japanese prime minister’s office declined to comment.

The episode highlights a new reality in U.S.-China relations. The trade truce with China and the issue of Taiwan have become inextricably linked, as the president and Xi prepare for several meetings next year. While official U.S. policy acknowledges without endorsing Beijing’s claim over the island, Washington has provided Taiwan with defensive arms, ensuring its fate isn’t determined by force from China.

Trump has praised Takaichi for her tough stance on defense and held an event with her aboard a U.S. aircraft carrier in the Japanese city of Yokosuka in a strong display of the two countries’ alliance.

But she has infuriated Xi at a bad time for Trump, as he cultivates a relationship with the Chinese leader.

Speaking to lawmakers on Nov. 7, Takaichi warned that Japan could deploy its military with other nations if China were to attack Taiwan. The remarks prompted Beijing to take retaliatory economic and diplomatic measures against Japan. A Chinese diplomat posted on social media that her neck should be cut off.

Trump’s call to Takaichi reflected the intense focus on Taiwan in the official Chinese account of their Monday discussion, the people briefed on the matter said. Xi told Trump that “Taiwan’s return to China is an important component of the postwar international order," the Chinese readout said.

In their phone conversation, Trump suggested to Takaichi that she temper the tone of her comments about Taiwan, the American briefed on the matter said, adding that Trump had been briefed on her domestic political constraints and was aware she likely couldn’t fully retract her comments that angered Beijing.

Tokyo’s position is that Takaichi was talking hypothetically and articulating longstanding Japanese policy, though it was unusual for a sitting prime minister to be so explicit.

Trump told reporters Tuesday night that he had “a great talk" with Takaichi. “We have a great relationship," he said. “She’s very smart, she’s very strong. And she’s going to be a great leader."

In a debate in Japan’s Parliament, Takaichi said Wednesday she hadn’t planned to get specific on Taiwan contingency, comments that some analysts see as a softening signal. “I didn’t intend to mention any specifics," Takaichi said, when a lawmaker asked her about the remarks that irked Beijing.

Analysts said the sequence of the calls—China first, then Japan—could reflect a willingness by Trump to curb an ally’s controversial stance on a core geopolitical issue in service of the U.S. trade relationship with Beijing.

“It’s not at all surprising for a U.S. president to talk to both the Chinese and Japanese leaders," said Matthew Goodman, a former Obama administration Asia specialist who focuses on geoeconomic studies at the Council on Foreign Relations. “But the order of the calls is interesting and likely raised some eyebrows in Tokyo."

The call between Trump and Xi highlighted what matters most to the two leaders.

A person close to the White House said the call was about trade, adding that Washington is concerned over China’s delaying implementation of its promised soybean purchases.

Trump said Tuesday night he told Xi that “I’d like you to buy a little faster," referring to China’s promised purchases of American farm products. “He’s more or less agreed to do that," he said.

Following Trump’s late-October meeting with Xi in South Korea, Washington said China agreed to purchase 12 million metric tons of soybeans by the end of the year and 25 million metric tons annually for the next three years. Beijing hasn’t issued an official statement confirming those numbers.

Taiwan was Xi’s overriding focus. While Xi didn’t name Japan or ask Trump to pressure Tokyo directly, the people said, his discussion of the post-World War II order was an implicit reference to Japan as the losing party, showing the depth of his concern over the recent tensions.

The Wall Street Journal has reported that Xi is chasing the ultimate concession from Trump, a pledge to “oppose" Taiwan’s independence. The State Department said at the time that the U.S. opposes “any unilateral changes to the status quo from either side" and that “China presents the single greatest threat to peace and stability in the Taiwan Strait."

Write to Lingling Wei at Lingling.Wei@wsj.com, Brian Schwartz at brian.schwartz@wsj.com, Meridith McGraw at Meridith.McGraw@WSJ.com and Jason Douglas at jason.douglas@wsj.com