[2] A key element of operations within the grey-zone is that they remain below the threshold of an attack which could have a legitimate conventional military response (jus ad bellum).
"[6] Grey zone warfare generally means a middle, unclear space that exists between direct conflict and peace in international relations.
According to Vincent Cable, examples of grey-zone activities include undermining industrial value chains or oil and gas supplies, money laundering, and the use of espionage and sabotage.
It can also be very hard for democratic states to respond to grey-zone threats because their legal and military systems are geared towards seeing conflicts through the sense of war and peace with little preparation or consideration for anything in between.
[19] However many of the unconventional tools used by states in the grey-zone such as propaganda campaigns, economic pressure and the use of non-state entities do not cross over the threshold into formalized state-level aggression.
China's artificial island building is done by dredging up massive amounts of sand and gravel, dumping it on top of pre-existing reefs.
[26] After creating these islands, China militarises them – radomes, gun turrets and close-in weapon systems for detecting and destroying incoming missiles and aircraft are common features on their artificial islands, and intelligence-gathering and submarine-hunting aircraft have been reported to “frequently operate from the airfield [in Fiery Cross].”[25] The militarisation of these islands deters access by rival military forces in areas China claims, increases the projection of Chinese power, and allows its armed forces greater room for manoeuvre in the event of a military conflict (e.g. in a potential invasion of Taiwan).
[31] The goal of the militia is to “establish [Chinese] presence in disputed areas, swarm and overwhelm other claimants’ activities, or reinforce Chinese presence claims under pressure.”[32] China has used their maritime militia to take territory from states with competing claims in the South China Sea, employing what Major General Zhang Zhaozhong of the PLA has referred to as the “cabbage strategy”.
[39] Even as Vietnam increases their artificial island building in the South China Sea, the Philippines has been content with this expansion, Philippine Navy Commodore Roy Vincent Trinidad stating, “Vietnam does not initiate illegal, coercive, aggressive and deceptive actions against us, unlike China.”[39] This sentiment was also echoed by Philippine Coast Guard Commodore Jay Tarriela, saying that Vietnam does not “engage in harassing our fishermen or illegally deploying coast guard vessels and maritime militia in the waters surrounding our occupied maritime features.”[39] China's grey-zone activity in the region has also prompted response from the US, who has conducted Freedom of Navigation Operations (FONOPS) in the region to maintain a steady presence and deter China's accumulation of gains.
[43] Every action taken in this area has a significant effect on the security situation in the rest of the region as these two economic behemoths go head-to-head in territorial disputes.
China's grey zone tactics include deploying state and state-supported vessels to harass foreign boats, normalizing its presence in disputed waters, and employing coercive measures to challenge opposing claims.
[45] From a Taiwanese perspective, China's strategy is described in four phases: initial incursions following specific incidents, normalization of presence, expanded control, and potential full-scale invasion.
[46] Other analyses suggest these activities aim to challenge the effective control of disputed territories, such as the Senkaku Islands, by demonstrating persistent Chinese presence and enforcement capabilities.
Chinese vessels have significantly increased their presence around the Senkaku Islands, engaging in activities such as patrolling, enforcing maritime law, and challenging Japanese fishing operations.
The increased presence of Chinese vessels in disputed waters has strained Japan's security system, which relies on a clear division of responsibilities between its Coast Guard and military forces.
[53] Observers note that while China employs unconventional methods to advance its maritime interests, the United States and its allies often adhere to traditional strategies, creating an imbalance.
As China continues to employ grey zone tactics, the ECS exemplifies the challenges of modern maritime governance and regional security dynamics.
There is, along with the Caspian Sea region, the closest area to the conflict-ridden Middle East, the Gulf and the Indian subcontinent, so it is bordering Central Asia, Afghanistan, Syria or Iraq.
[55] This connection provides Europe with more energy resources, natural gas, metals and rare earth, in addition to increased trade and transit for emerging markets in the broader region.
The Kerch Strait shipping routes went through Ukrainian territorial waters thanks to this island, Significantly, the formal customers of the construction were private individuals affiliated with Russian paramilitary Cossack organizations.
The conflict was resolved by halting construction and signing the Agreement Between the Russian Federation and Ukraine on Cooperation in the Use of the Sea of Azov and the Kerch Strait.
Some authors suggest that the legal uncertainty derived from the challenged status of Crimean coastal waters and the Kerch Strait Bridge security regulations was utilized to operate in a ‘gray zone’ to complicate decision-making for other states.
[57] On 21 June 2021, Russian patrol ships allegedly fired warning shot to a British warship, the HMS Defender which was siling from Odesa to Georgia within the annexed Crimea's territorial water and a Su-24 M craft dropped four bombs along the vessel's path.
In addition, document confirms that the passage was a calculated decision by the British government and that the use of the warship was in pursuit of coercive diplomatic goals.
On top of that, Ukrainian leadership generally considered the confrontation with Russia primarily at the ground domain of war, neglecting the naval component's development.
[57] They tried to the recovery of surface forces up to 2030 by deploying boats of the ‘mosquito fleet’ supported by coastal artillery, but this project was abandoned due to technical difficulties.
[60] And also NATO's Comprehensive Approach to deterrence that emerged from the 2011 Lisbon Summit Declaration is a step toward countering unconventional threats, but empirical evidence from the Baltics shows that it has yet to be sufficiently effective in remedying the key areas that enable the use of diaspora-related gray zone tactics.