Russia began its largest war games since the Cold War on Tuesday, drilling hundreds of thousands of troops alongside forces from its growing ally China.
With 300,000 soldiers, 36,000 vehicles, 1,000 aircraft and 80 ships, the Vostok exercises in eastern Russia will be even bigger than the Zapad training conducted by the Soviet Union in 1981, according to the defence minister.
They will last five days and take place across nine training grounds, the Sea of Japan and the Bering Strait.
It will be a triumphant moment for Vladimir Putin, who has made the military's modernisation a top priority following its post-Soviet stagnation and highlighted fantastic-sounding new nuclear weapons in his state-of-the-nation speech in March.
Preliminary manoeuvres have involved launching dummy torpedos at warships in the Sea of Okhotsk and shooting down cruise missiles and drones in Tajikistan.
Coming a week before a summit between the leaders of North and South Korea, the war games will reiterate Moscow's bid to be a major military and diplomatic player in the region.
Some are speculating that one of the scenarios to be trained for will involve a nuclear conflict on the Korean peninsula.
Vostok, however, is not only a display of Russia's fighting power, but also a promotion of its warming ties with eastern neighbour and former foe China.
Xi Jinping will meet with Vladimir Putin this week at the eastern economic forum in Vladivostok. The Russian president is also expected to make an appearance at the Vostok manoeuvres.
Although China has previously joined Russia for drills like naval games in the Baltic Sea last year, this is the first time it will participate in Moscow's annual strategic exercises, which practice the management of far-flung forces in a large-scale conflict.
The People's Liberation Army and air force will send 3,200 troops and 30 aircraft to the Tsugol training grounds east of Lake Baikal.
Russia has said it will train methods developed during its military intervention in Syria, giving Chinese forces - which haven't fought in a war since 1979 - a glimpse of real combat skills.
The unprecedented manoeuvres are being seen as a warning to Washington not to further strain relations with Russia or provoke it militarily.
“It's clear that such efforts can be directed at only one country, and that's United States, because they're so massive,” said Vasily Kashin, an expert in Russia-China relations at the Higher School of Economics.
“At this moment Russia and China both see the United States as the main potential military adversary.”
In light of successive waves of US sanctions against Russia and Donald Trump's trade war with China, America is now the main political adversary for both countries as well.
They have frequently voted together against US resolutions in the United Nations security council in recent years, and Russia has increasingly sought Chinese credit and investment after being cut off from US financing.
Having overtaken Saudi Arabia as China's largest oil supplier in 2016, Russia is building the Power of Siberia pipeline in hopes of beginning gas deliveries there by the end of next year.
In some ways, Mr Putin's pivot east at the expense of the US looks like a final reversal of Richard Nixon's 1972 rapprochement with China, which was meant to unsettle the USSR.
The Kremlin's spokesman said last month the manoeuvres showed the “expansion of cooperation in all spheres between two allies”.
While the term may be overstated given Moscow and Beijing's stated aversion to binding alliances, the quickening development of relations could eventually lead to a formal agreement, according to Mr Kashin.
“Every year steps are taken, and that will continue until it reaches its logical conclusion, probably some military pact that has obligations in case war arises,” he said.
But independent defence analyst Alexander Golts argued that China's invitation to participate was mainly to allay concerns that these enormous Cold War-style exercises on its border would otherwise raise.
“These manoeuvres aren't just unprecedented for Russia. No one is doing exercises of this size today,” he said.
The expensive military exercises come at the same time as an unpopular reform that will raise the pension age to just a year below average life expectancy for Russian men.
More than 1,000 people were arrested protesting the reform in cities around Russia on Sunday.
But the Kremlin's spokesman said last month defence spending was “justified, necessary and has no alternative” given the international threats faced by Russia.