Updated at 10:30 A.M. E.D.T.

SEOUL — In the intricate game of Asian power moves, no sooner had President Biden strengthened relations with America’s historic communist enemy, Vietnam, than the North Korea party boss was reported on his way to see the man who may be our worst enemy, President Putin.

The one-two sequence dramatized the hardening of lines from Ukraine to the Korean peninsula after Mr. Biden said his visit to Hanoi was “not about containing China.”

Word that North Korea’s Kim Jong-un was on his way by train to see Mr. Putin at Russia’s Pacific port city of Vladivostok deepened America’s most immediate concern in the region — that North Korea may formalize a deal for providing Moscow with all the artillery shells the Russians need for prosecuting their war in Ukraine.

Against dire American warnings of “consequences,” neither Mr. Kim nor Mr. Putin was believed to have the slightest compunction about ordering a huge jump in the number of shells that North Korea has already been secretly selling to the Russians. That deal was expected to precede a sharp increase in export to Russia of weaponry made in North Korea at far lower prices than it costs to make military hardware in Russia.

Mr. Kim, building on talks between North Korea and Russian officials in recent weeks, was expected to see Mr. Putin during an economic forum Tuesday and Wednesday at Vladivostok, where he first met the Russian president more than four years ago.

The impending Russian-North Korean summit upstaged the signing by Mr. Biden and Vietnam’s leader, Nguyen Phu Trong, of a “comprehensive strategic partnership” upgrading the “strategic partnership” formed by President Obama and Mr. Trong 10 years ago. Mr. Trong’s role as general secretary of the country’s omnipotent Communist Party places him above the level of the country’s president and prime minister.

The White House cast the upgrade in euphoric verbiage, describing the move as “unprecedented and momentous,” resulting from “intense efforts by both governments to establish and build mutual understanding and to chart a forward-looking path…..”

The deal, though, carefully skirted any suggestion of military significance, including the possible sale of arms, much less a military alliance for defense against Vietnam’s northern neighbor, China, with which Vietnam fought a border war in 1979. 

Nor did the Americans and Vietnamese, in all their statements, say a word about China’s takeover of access to natural gas deposits in competition with Vietnam in the South China Sea that may have prompted the American-Vietnamese lovefest at Hanoi.

Washington and Hanoi now enjoy a partnership on the same level as Vietnam’s relations with China and Russia as well as India and South Korea. Beijing and Moscow both provided Hanoi a steady flow of weaponry throughout the Vietnam War, and Hanoi reportedly is negotiating with Moscow to buy still more weapons.

The understandings worked out during Mr. Biden’s visit, though, were entirely economic. 

It was chips, not shells or bullets, that counted in the talks in which Mr. Biden and Secretary Blinken convened what they called “a U.S.-Vietnam Innovation and Investment Summit with U.S. and Vietnamese industry leaders,” at which they discussed “priorities for expanding technology and economic cooperation, including Vietnamese investments in the United States.”

At the top of what the White House called “an ambitious set of new initiatives” was a promise “to support resilient semiconductor supply chains for U.S. industry, consumers and workers” that “recognizes Vietnam’s potential to play a critical role.”

Russia was also reported holding out “technology” for North Korea as a reward for North Korean weapons. The “technology,” though, is believed to be military. A website at Seoul, NK News, reported the South’s National Intelligence Service as saying, “North Korea may have requested technological support to fix outdated military equipment and rent ‘Western-made weapons.’”

Much about the summit, however, remained shrouded in mystery. Both the Russian news agency, Tass, and Pyongyang’s Korean Central News Agency confirmed Messrs. Putin and Kim would meet but did not say exactly where or when.

Tass said only that Mr. Putin had invited Mr. Kim to his country “in coming days” while KCNA said they would “meet and have a talk.”

Mr. Kim’s eagerness to see Mr. Putin again reflected his anxiety for a friend other than China, from which North Korea imports most of its oil and half its food. He’s hoping to get more oil from Russia along with food shipments by rail across the final 11 miles  of the Tumen River before it empties into the sea.

China has remained somewhat aloof from Mr. Biden’s visit to Hanoi as well as Russia’s dealings  with North Korea.

The director of the Center for Southeast Asian Studies at the Chinese Academy of Social Sciences, Xu Liping, told Global Times, a Chinese propaganda newspaper, that “the elevation of the US-Vietnam relationship is just a symbolic gesture.” In a warning to Vietnam, he added darkly, “Excessive support could pose a threat to other countries.”

The prospect of an arms deal between North Korea and Russia obscured not only the dividends of the Hanoi summit but also the pleasant-sounding outcome of the G20 hosted by India’s Prime Minister Narendra Modi in New Delhi. 

Messrs. Xi and Putin skipped the event, but their surrogates, China’s premier, Li Qiang, and the Russian foreign minister, Sergei Lavrov, were able to sign off on the delicately worded final communique.

“All states must refrain from the threat or use of force to seek territorial acquisition against the territorial integrity and sovereignty or political independence of any state,” they all agreed. “The use or threat of use of nuclear weapons is inadmissible. “

No such diplomatic sweet talk was expected from Messrs. Putin and Kim as they usher in what could be a more intense, bloody phase of a war that shows no sign of ending.