Russia is about to kick off a war game that is freaking out NATO — here's what we know

Every four years, Moscow conducts its large Zapad military exercises in western Russia and Belarus for six days, and this year it will engage the fictional country of Veishnoriya in a test of its defensive capabilities.

The war games began in the 1970s, but they weren't held after the fall of the Soviet Union until they were reinstituted in 1999.

The basic premise of the games is that Veishnoriya, in reality located in Belarus, is being taken over by Western-backed militias — "zapad" means "west" in Russian — with the help of two other fictional Western-backed countries, Lubeniya and Vesbasriya, according to The New York Times. They are scheduled to end on Wednesday.

But NATO has been fretting about these exercises for two reasons.

The first is that it claims Moscow is hiding the true number of the troops taking part in them.

Russia officially says the games will involve 12,700 troops — under the 13,000 that would require foreign observers, according to the Vienna Document — while NATO has estimated that number to be about 70,000 to 100,000 or more.

The disparity in these estimates is mainly because of a disagreement over whether to count civilian officials and security agents as part of the overall number.

It's also because Russia might conduct smaller exercises in the area that are not technically part of Zapad. And the West tends to count full units as having participated in exercises when, in fact, only parts of units were there.

Either way, that "100,000 figure is pretty off the wall," Mark Galeotti, a senior research fellow at the Institute of International Relations Prague, previously told Business Insider in an email.

Several other analysts have told Business Insider much the same thing.

Sim Tack, the chief military analyst at Force Analysis, and Dmitry Gorenburg, a senior research scientist at CNA, told Business Insider that the 100,000 figure came from an amateur Ukrainian blog that miscalculated the number based on the total train cars that Moscow said it would use to transport troops to the games.

Tack said that "a lot of people have just copied that" Ukrainian blog, which Margus Tsahkna, Estonia's former defense minister, first started spreading.

In any event, "it's hard to know how many troops will be in" this year's Zapad exercises because of the disagreement over who should be counted, Galeotti said.

The second thing NATO has been worried about is that Russia might use the games to covertly keep some of its forces in Belarus permanently, effectively driving a spearhead into NATO's lines.

"People are worried this is a Trojan horse," US Army Lt. Gen. Ben Hodges told Reuters in July. "They say, 'We're just doing an exercise,' and then all of a sudden they've moved all these people and capabilities somewhere."

Tsahkna also told Reuters: "For Russian troops going to Belarus, it is a one-way ticket."

But the "likelihood of this exercise serving as cover for some larger nefarious aim, whether it is an attack on Ukraine or Lithuania or a stealth occupation of Belarus, is practically zero," Gorenburg wrote in The National Interest.

It's "highly unlikely the Russians would park troops in Belarus uninvited," Galeotti said. "Minsk has already made it clear that it would not welcome this," and Moscow doesn't have the budget to maintain troops there.

And while some have even said that the West seeing Zapad as a threat helps Moscow by making Russia seem more powerful than it is, NATO has still deployed four international battalions to Poland, Lithuania, Latvia, and Estonia for safety precautions.

But others have said that instead of panicking about the games, the West should use them to study Russia's military capabilities, which have transformed and been restructured in many ways since the rise of Russian President Vladimir Putin, who will oversee the exercise.

"The exercise is actually a very good opportunity for us to ... get a better sense of what the Russian military is actually capable of: how it can handle logistics, move different units, or, in an operation, exercise command and control over combined armed formations in the Baltic theater, which is the one we're principally concerned with, right?" Michael Kofman, a research scientist at CNA, told Radio Free Europe/Radio Liberty.

"As we've seen before, Russians train exactly as they intend to fight," Kristjan Prikk, the undersecretary for policy at the Estonian Defense Ministry, said at an Atlantic Council event, according to Radio Free Europe/Radio Liberty. "Thus, Zapad will give ample information on their military development and certainly on their political thinking, as it is right now."