Late August and early September appears to be the season for major military maneuvers. The recent 11-day Ulchi Freedom Guardian drill on the Korean Peninsula was enormous. Some 50,000 South Korean troops and 17,500 US soldiers, largely using computer simulations, practiced what to do if North Korea launched an invasion.

It was also not unusual – the two countries carry out the operation at the end of August ever year, though of course that did not stop North Korea condemning it as a preparation of invasion.

Meanwhile on the other side of the world, Moscow is about to launch its seven-day Zapad exercises in northwestern Russian and allied Belarus, involving nearly 13,000 soldiers, and drawing demands from the German Defense Ministry for more transparency.

With these two scheduled events, coupled with heightened tensions around the world, countries regularly conduct military exercises to test their procedures and tactics.

Why be transparent?

But whether the exercises are carried out by single countries or by military alliances, there are few international rules governing such operations.

There are regional exceptions. The Organization for Security and Cooperation in Europe (OSCE) did draw up some rules governing military operations in its 2011 Vienna Document. Designed to promote transparency, this documents stipulates, among other things, that OSCE states, which include Russia, give 42 days' prior notification of "Certain Military Activities" for operations of over 9,000 troops, and it must invite all OSCE states to observe such activities if they exceed the 13,000-troop threshold.

These rules are mainly designed to build trust between the signatories and to prevent such training exercises from spiraling into open conflict in Europe. But, as Sebastian Schulte of Jane's Defence Weekly pointed out, "the OSCE rules are not in the form of a formal treaty, but rather that of a non-binding status."

"In reality, not adhering to these self-imposed restrictions concerning military exercises leads the buildup of trust to unravel and 'bad press,' but no direct penalties as organizations such as the OSCE or the UN are in no position to enforce any legal or political sanctions," he said.

A gentleman's agreement

In fact, Schulte calls the OSCE regulations "soft indicators," whose purpose is to help identify "when and where one of the signatories is leaving the agreed upon group consensus, rather than hard law that prohibits and penalizes certain behavior."

In other hot spots, such as the Korean peninsula, the rules are even softer – in effect, they are little more than "gentleman's agreements" designed with a similar intention to the OSCE's rules in Europe.

"The difficulty lies of course with the fact, that by definition a nation's military and its military affairs are at the core of any nation's sovereignty," said Schulte. "In other words, a country that lets a foreign entity, state or organization dictate its military policies, isn't really sovereign."

On the other hand, obvious secrecy concerns notwithstanding, countries have many good reasons to keep their military exercises transparent. For one thing, it's a good idea to announce a major exercise in advance to avoid surprising your neighbors and to make sure they don't think they are veiled build-ups for an invasion. For another, most countries publish the schedule of their exercises in advance to show off their military potency.

For its part, NATO has recently stepped up its military exercise program in light of what it called the "changed security environment" around the world.

According to the current schedule, as many as 100 NATO exercises are planned for this year, plus 149 national exercises led by individual member countries, which represents a slight increase from 2016.

Also, NATO claims that its military exercises are harmless – and about seeking "transparency and predictability, not confrontation." In 2016, 17 of its exercises were made open to observers from partner countries, as well as from international organizations like the European Union.