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RETHINKING CHINA’S GRAY-ZONE STRATEGIES: CASES FROM THE EAST
CHINA SEA, SOUTH CHINA SEA, AND TAIWAN STRAIT
HSIAO-CHUAN LIAO
mandyliao@ntu.edu.tw
She is Taiwanese scholar and Associate Professor in the Department of Political Science, National
Taiwan University, Taipei (Taiwan). She received her Ph.D. in Department of Political Science
from University of South Carolina, U.S.A. Her research interests include international conflict,
international relations theory, foreign policy and decision-making, Sino-US-Japan relations, and
Indo-Pacific security studies. Her research has appeared in the referred journals such as Asian
Politics and Policy, Issues & Studies, Taiwan Political Science Review, Taiwanese Journal of
Political Science, and Chinese Political Science Review. ORCID: 0000-0003-0041-9066.
Abstract
This paper investigates China’s gray-zone strategies in the South China Sea, East China Sea,
and Taiwan Strait, addressing how China’s use of non-military gray-zone strategies differs
across these three maritime regions and what implications these variations hold for regional
security. This study redefines gray-zone strategy as a country’s attempt to change or influence
another country’s sovereignty rights or policies through governmental or non-governmental
actions, which is different from military brinkmanship. It identifies five categories of non-
military gray-zone tactics: narrative warfare, psychological warfare, legal warfare, mixing of
civilian and military activities, and governmental jurisdiction warfare. Based on a comparative
case analysis of the three areas, the study finds two key characteristics. First, China adopts
military means for severe sovereignty violations while relying on non-military gray-zone
strategies for lesser infringements to avoid escalation. Second, the greater the perceived
impact on sovereignty, the more China employs riskier gray-zone tactics. In the South China
Sea, China employs all five tactics to expand economic sovereign rights and create an order
alternative to the U.S.-led liberal international order. In the East China Sea, it leverages
narrative and jurisdictional tactics to undermine Japan’s control while avoiding military
confrontation. In the Taiwan Strait, psychological warfare dominates as China seeks to
internalize the strait and domesticate Taiwan. Overall, the paper suggests collective,
asymmetric responses targeting China’s vulnerabilities to enhance deterrence and maintain
regional stability.
Keywords
Gray-zone strategy, China, South China Sea, East China Sea, China, Taiwan Strait.
Resumo
Este artigo estuda as estratégias de zona cinzenta da China no Mar da China Meridional, Mar
da China Oriental e Estreito de Taiwan, abordando como o uso de estratégias de zona cinzenta
não militares pela China difere nessas três regiões marítimas e quais as implicações dessas
variações para a segurança regional. Este estudo redefine a estratégia de zona cinzenta como
a tentativa de um país de alterar ou influenciar os direitos ou políticas de soberania de outro
país por meio de ações governamentais ou não governamentais, o que é diferente da política
de risco militar. Ele identifica cinco categorias de táticas não militares de zona cinzenta: guerra
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Rethinking China’s Gray-Zone Strategies: Cases from the East China Sea, South China Sea,
and Taiwan Strait
Hsiao-Chuan Liao
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narrativa, guerra psicológica, guerra jurídica, mistura de atividades civis e militares e guerra
de jurisdição governamental. Com base em uma análise comparativa de casos das três áreas,
o estudo identifica duas características principais. Primeiro, a China adota meios militares
para violações graves da soberania, enquanto confia em estratégias não militares da zona
cinzenta para infrações menores, a fim de evitar uma escalada. Segundo, quanto maior o
impacto percebido sobre a soberania, mais a China emprega táticas mais arriscadas da zona
cinzenta. No Mar da China Meridional, a China emprega todas as cinco táticas para expandir
os direitos de soberania económica e criar uma ordem alternativa à ordem internacional liberal
liderada pelos EUA. No Mar da China Oriental, ela usa táticas narrativas e jurisdicionais para
minar o controle do Japão, evitando o confronto militar. No Estreito de Taiwan, a guerra
psicológica domina, à medida que a China busca internalizar o estreito e domesticar Taiwan.
No geral, o artigo sugere respostas coletivas e assimétricas direcionadas às vulnerabilidades
da China para aumentar a dissuasão e manter a estabilidade regional.
Palavras-chave
Estratégia da zona cinzenta, China, Mar da China Meridional, Mar da China Oriental, China,
Estreito de Taiwan.
How to cite this article
Liao, Hsiao-Chuan (2025). Rethinking China’s Gray-Zone Strategies: Cases from the East China
Sea, South China Sea, and Taiwan Strait. Janus.net, e-journal of international relations. VOL. 16,
Nº. 2, November 2025-April 2026, pp. 118-136. DOI https://doi.org/10.26619/1647-7251.16.2.7
Article submitted on 10th July 2025 and accepted for publication on 26th September
2025.
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Rethinking China’s Gray-Zone Strategies: Cases from the East China Sea, South China Sea,
and Taiwan Strait
Hsiao-Chuan Liao
120
RETHINKING CHINA’S GRAY-ZONE STRATEGIES: CASES FROM
THE EAST CHINA SEA, SOUTH CHINA SEA, AND TAIWAN STRAIT
HSIAO-CHUAN LIAO
Introduction: China’s Gray-zone Actions
On June 17, 2024, the China Coast Guard (CCG), supported by maritime militia and the
People’s Liberation Army Navy, surrounded, rammed, and boarded a Philippine Navy
inflatable boat while it was conducting a resupply mission to Second Thomas Shoal.
During the incident, CCG personnel used knives, bats, and axes to damage the Philippine
boat, resulting in one Philippine navy serviceman losing his right thumb (Asia Maritime
Transparency Initiative, 2024). Although the Philippine government quickly squelched
speculation that the event might invoke the 1951 Philippines–U.S. Mutual Defense Treaty
(Gomez, 2024), continued CCG aggression in the South China Sea makes it increasingly
likely that the treaty could be invoked in the near future. Philippine President Ferdinand
Marcos has stated that the treaty would “kick into action” if a “Filipino serviceman is killed
because of an attack or an aggressive action by another foreign power” (Gutierrez, 2024).
Similar incidents have occurred in the East China Sea, where the CCG frequently patrols
disputed areas claimed by Japan. The frequency of these patrols increased dramatically
after Japan nationalized the Diaoyu/Senkaku Islands in 2012, and hot pursuit events
involving the Japanese Coast Guard (JCG) have become almost routine. Beyond the
South China Sea and East China Sea, the CCG has also extended its so-called law
enforcement operations to the Taiwan Strait. On February 14, 2024, two Chinese
fishermen died while fleeing from Taiwan’s Coast Guard after being intercepted for illegal,
unreported, and unregulated (IUU) fishing in waters under Taiwan’s administration.
1
Subsequently, the CCG began patrolling prohibited and restricted waters around Taiwan’s
Kinmen Islands, claiming that these patrols constitute normal law enforcement.
These are aggressive actions by the CCG; however, China also engages in other tactics
such as deploying maritime militia to surround disputed islets and sever their connections
to other claimants, issuing fishing bans in disputed seas, and promoting historical rights
narratives in the South China Sea. Such actions are considered gray-zone strategies.
While they may not lead to war like direct military actions, they can incrementally change
the status quo. The U.S. Quadrennial Defense Review (QDR) in 2010 noted that many
changes fall within this ambiguous gray zone, including military mobilization, economic
warfare, and information warfare (Secretary of Defense, 2010). These gray-zone
1
At around 1 p.m. on February 14, 2024, a Chinese speedboat carrying four people crossed the maritime
boundary and intruded into the waters near Kinmen. When it refused inspection, Taiwan’s Coast Guard pursued
the vessel, during which the speedboat capsized, resulting in two fatalities and two survivors (Wu, 2025).
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strategies have increasingly raised regional concerns. How can such actions be
distinguished conceptually? Are there differences in China’s gray-zone strategies across
the East China Sea, Taiwan Strait, and South China Sea? This paper first examines the
literature on gray-zone strategies, arguing that the concept requires greater specificity
to be meaningful. Furthermore, it contends that China is more likely to adopt gray-zone
strategies in areas with multiple disputing states to maximize their “avoidance of war”
effect. The comparison of the three seas supports this argument.
Gray-zone strategy: Origin and Literature
Gray-zone strategies are not a modern invention in the realm of national strategy. If one
adopts a broad definition of strategies that operate between war and peace, such
concepts can be traced back to ancient China. Sun Tzu, the renowned military strategist
from the Spring and Autumn period, articulated in The Art of War that the highest form
of strategy is to subdue the enemy without fighting, compelling surrender without
deploying troops or attacking the enemy directly. In modern history, the Cold War
exemplified gray-zone dynamics, as the United States and the Soviet Union avoided
direct warfare yet engaged in proxy wars, psychological operations, infiltration, and arms
races—tactics that fall within the broad spectrum of gray-zone strategies. The term
“gray-zone” first appeared in an official U.S. government document in the 2010
Quadrennial Defense Review, which noted that future challenges would increasingly
emerge in ambiguous areas between war and peace. The report suggested that
strengthening allies to respond to such challenges would reduce risks to U.S. forces and
extend security to areas where unilateral action was impractical (Secretary of Defense,
2010).
In East Asia, Japan experienced a gray-zone crisis in September 2010 with the “Minjin
Fishing Vessel 5179 Incident,” when a Chinese trawler collided with a Japanese Coast
Guard vessel near the Diaoyu/Senkaku Islands (Bau, Tso, & Liao, 2014). The Japanese
government is aware that civilian or paramilitary forces are being used to change the
status quo while compelling the targeted country to take the initiative in settling the
situation through some form of force. These incursions blur the line between crime and
defense, as well as between law enforcement and military activities (Pajon, 2017).
Japan’s 2010 National Defense Program Guidelines subsequently identified China’s
growing maritime activities—including coast guard and fishing vessel incursions—as
gray-zone challenges involving sovereignty disputes short of outright conflict. Tensions
escalated after Japan nationalized the Diaoyu/Senkaku Islands in 2012, with frequent
incursions by Chinese military aircraft and CCG ships attempting to establish a “new
normal.” Scholars have examined China’s systematic use of such tactics. Holmes and
Yoshihara (2012) argue that drawing from Mahan’s sea power theory, China employs
gray-zone strategies to expand maritime influence, as seen in the 2012 Scarborough
Shoal standoff, where China used non-combat maritime militia vessels to occupy the
shoal without conventional military force—an approach they term “small-stick
diplomacy.” Denny Roy (2015) similarly notes that China’s tactics in the East and South
China Seas are aggressive yet calibrated to avoid provoking direct military retaliation.
Zhang (2019, pp. 119–120) describes China as a “cautious bully,” noting that it uses
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military coercion less frequently as it becomes stronger. This suggests that focusing
solely on the growth of China’s material capabilities cannot fully explain its behavior.
Mazarr (2015) provides a comprehensive analysis, asserting that China’s gray-zone
strategies aim to establish a China-led order in the South China Sea. He categorizes gray-
zone tactics into six types by intensity: narrative warfare, denial of prosperity, civilian
intervention, active infiltration, coercive signaling, and proxy sabotage. For instance,
China uses narrative warfare to assert historical claims and economic measures to coerce
rivals, while deploying civilian organizations to consolidate control, as in Scarborough
Shoal. Mazarr warns that while these tactics may avoid immediate conflict, they risk
increasing international tensions and escalating into war. McLaughlin (2022) argues that
gray-zone operations are designed to “exploit or create legal uncertainties for a military
or strategic advantage.”
Beyond China, states like Russia also employ gray-zone strategies, such as annexing
Crimea by infiltrating masked troops, installing a proxy government, and legitimizing
annexation through a referendum. Chen Yong (2019) defines gray-zone strategies as
competitions between states or between state and non-state actors within the spectrum
between war and peace, highlighting their ambiguity and risk. Barno and Bensahel (2015)
caution that such strategies, though non-traditional, can threaten core U.S. interests.
Brands (2016) similarly describes them as coercive and aggressive tactics disguised as
non-military conflict to alter the status quo, terming them “gray-zone conflicts.”
Finally, Cheng and Hung (2019) argue that the challenges posed by gray-zone strategies
stem not from the tactics themselves but from the power of the actors employing them.
They contend that these strategies are ultimately peaceful forms of conflict resolution,
echoing Sun Tzu’s notion of winning without fighting. The case study of the Philippines
also demonstrates that China’s gray-zone strategies are intended to induce a sense of
helplessness in other countries, causing them to either acquiesce or become numb to
China’s actions. Although the Duterte administration initially acquiesced, it later shifted
its policy and responded to China’s actions with greater resolve (de Castro & Chambers,
2022). Nonetheless, American scholars largely view these strategies as expressions of
non-military coercion intended to change the international order. For example, a
publication by the Center for Strategic and International Studies (CSIS) notes that the
U.S. Department of Defense has employed Freedom of Navigation Operations (FONOPs)
to deter China’s gray-zone activities threatening sea lanes in the Indo-Pacific region, and
has also partnered with the Philippines to publicly expose China’s actions in the area as
a way of countering its gray-zone strategies (Sheppard et al., 2019, pp. 27, 62).
Adjust Gray-zone Strategy
Revise definition
The literature on gray-zone strategies reveals that the most common definition refers to
strategies that lie between war and diplomacy. These encompass military, economic,
social, and political actions characterized by aggression aimed at expanding one’s power
to gradually change the status quo. Zheng and Hong (2019) summarize four
characteristics of gray-zone strategies: revisionism, asymmetry, ambiguity, and
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gradualism. In terms of objectives, gray-zone strategies seek to incrementally alter the
status quo by leveraging asymmetries in capabilities and costs between themselves and
their adversaries. This approach operates below the threshold of war, avoiding direct
military retaliation and introducing ambiguity regarding whether a given action
constitutes preparation for war and how it should be countered. Ultimately, gray-zone
strategies yield gradual effects akin to “salami slicing,” making it difficult for neighboring
countries to respond effectively. However, Dai Zheng and Hong You-sheng’s compilation
of definitions and tactics indicates that the broad conception encompasses a wide array
of actions, such that any move hindering another country’s interests without declaring
war may be labeled a gray-zone strategy. This broad definition dilutes the perceived
security threat and opportunities for counteraction.
2
Therefore, it is necessary to distinguish between military and non-military tactics. Mixing
military tactics with non-military ones under the same label risks diminishing the severity
of military tactics and the significance of non-military ones. Military tactics should not be
considered gray-zone strategies. While the term “gray-zone” originally aimed to capture
strategies that breach peace without provoking war, military tactics are preparations for
war and are likely to trigger escalation. Thus, they should be treated as strategies with
the potential for war, rather than as gray-zone strategies.
Specifically, Russian General Valery Gerasimov’s (2013) concept of “hybrid warfare”
asserts that modern warfare increasingly employs unconventional and non-traditional
forces, including private military companies and hybrid tactics, as a new norm of warfare.
These are methods designed for war and carry a high potential to escalate into conflict.
This is also why Patalano (2018) argues that the concept of gray-zone strategy adds little
nuance to the existing literature on state warfare and strategy. That is, this kind of tactics
are considered as methods for war and are possible to lead to war. Cooper and Shearer
(2017) also argues that China’s adoption of gray-zone approaches differs from Russia’s
hybrid warfare, as China focuses on accumulating influence through economic means and
non-military tactics while deliberately avoiding direct combat.
This distinction also clarifies the difference between brinkmanship and gray-zone
strategies. Brinkmanship involves using military tactics to demonstrate a willingness to
go to war, aiming to persuade the target state that confrontation is approaching the
threshold of armed conflict. In contrast, a state adopting gray-zone strategies signals
that it does not seek war, instead employing limited non-military measures to change
the situation incrementally without provoking strong objections. In summary, both
strategies aim to avoid war, but brinkmanship involves military tactics and bluffing
readiness for war, while gray-zone strategies reveal a lack of willingness to fight and
prioritize non-military tactics.
Including military tactics under the umbrella of gray-zone strategies also diminishes the
significance of non-military tactics. States may downplay an adversary’s gray-zone
moves, perceiving them as insufficient to warrant military concern, thereby enabling
incremental salami-slicing changes to the status quo. Distinguishing military from non-
military tactics helps spotlight gray-zone moves so that states can respond proactively.
2
This section incorporates content from Liao (2022).
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A precise definition of gray-zone strategies’ objectives, timing, and tactics is necessary.
This paper defines gray-zone strategies as a country’s attempt to change or influence
another country’s sovereignty rights or policies through governmental or non-
governmental actions, thereby redefining mutual strategic interests. The ultimate goal
remains the preservation of national security and sovereignty within the traditional
security domain, even if non-state actors are involved. These actions are driven by
national motives aimed at securing state interests rather than private interests. While
the executors of operations may include state or non-state actors, planning and
command must originate from the state. Thus, non-state actors’ independent actions
that accidentally violate another state’s sovereignty should not be considered gray-zone
strategies.
Gray-zone Tactics
As for tactics, this paper argues that only non-military tactics constitute gray-zone
strategies. Specifically, gray-zone tactics include narrative warfare, legal warfare,
governmental jurisdiction warfare, psychological warfare, and mixing of civilian and
military activities.
Narrative warfare refers to the contest for discursive authority, exemplified by China’s
invocation of historical rights to justify its maritime claims and territorial demarcation in
the South China Sea. Legal warfare manifests in two forms: first, the use of domestic
legislation to regulate the behavior of foreign actors; second, efforts to seize interpretive
authority over international laws and customary norms. For instance, China has
increasingly invoked its reading of UNGA Resolution 2758 to legitimize its One-China
Principle and delegitimize Taiwan’s status as a separate political entity in the international
system. The third category, governmental jurisdiction warfare, is exemplified by the
China Coast Guard’s (CCG) law enforcement activities in disputed waters and the
imposition of summer fishing bans in the South China Sea, both unilaterally asserting
jurisdiction over foreign actors in contested areas. This category also encompasses denial
of prosperity tactics, such as economic sanctions or trade quarantines to coerce a target
state.
Psychological warfare includes espionage, active infiltration, proxy sabotage, and
propaganda. Although these tactics have long existed in traditional diplomatic practices,
they become gray-zone strategies when directed aggressively toward a specific
adversary. For example, Russia’s annexation of Crimea was preceded by an integrated
campaign of psychological warfare: masked troops seized key strategic locations, a pro-
Russian local government was installed through proxies, and a referendum was held to
legitimize annexation. Lastly, mixing civilian and military activities involves utilizing
civilian forces to hinder foreign operations or conceal military objectives. The facilities
constructed by China in the South China Sea exhibit dual-use characteristics, extending
its military projection capabilities. Through deploying maritime militia forces to encircle
Scarborough Shoal, China ultimately established effective control over the disputed area.
This definition and typology align with Sun Tzu’s classification of national strategy. In The
Art of War, Sun Tzu wrote: “The best warfare is to win by strategy, followed by diplomacy,
then military action, and lastly, besieging cities.” Ideally, a country influences or changes
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another state’s sovereignty rights or policies through cunning strategies, achieving
objectives without deploying troops. The second approach involves diplomatic measures
to disrupt alliances, the third entails military engagement, and the least desirable is direct
territorial occupation. Thus, gray-zone strategies correspond to the first type: “winning
through strategy,” where the adversary perceives confrontation as too risky and success
as unlikely, leading to the abandonment of resistance.
Based on this definition, gray-zone strategies are crucial for safeguarding national
sovereignty. Understanding how a country can employ gray-zone strategies to protect
its own interests and how it can respond to others’ gray-zone strategies is essential for
maintaining the status quo. When a state employs gray-zone strategies, its goal is to
signal that confrontation carries significant risks, compelling the opponent to adjust
policies accordingly. Effective responses should therefore focus on addressing the
underlying objectives of such strategies rather than merely reacting to their methods, in
order to mitigate risks and counter their impacts effectively.
Theorizing China’s Gray-zone Strategy
China has actively employed gray-zone strategies in the Indo-Pacific region in recent
years. However, the frequency and types of these strategies vary. The following sections
examine the three maritime areas in the Indo-Pacific where China employs gray-zone
strategies for different purposes, thereby shaping regional dynamics and destabilizing
the status quo.
South China Sea: Struggle between Two Orders
Since the end of World War II, the U.S.-led order of free and open international seas has
become the global mainstream. Although the United States has not ratified the 1982
United Nations Convention on the Law of the Sea (UNCLOS), its norms—such as the
delineation of the high seas—continue to guide state conduct in maritime domains. In
the South China Sea, China, Vietnam, Malaysia, Brunei, the Philippines, and Taiwan
assert overlapping maritime claims. China claims maritime rights within the so-called
ten-dash line, effectively encompassing almost the entire South China Sea. Taiwan claims
that Taiping Island (Itu Aba) qualifies as an island entitled to a 200-nautical-mile
Exclusive Economic Zone (EEZ), overlapping with claims by Vietnam, Malaysia, the
Philippines, and Brunei.
China’s gray-zone strategies in this area are highly diversified, encompassing narrative
warfare, legal warfare, governmental jurisdiction warfare, psychological warfare, and the
mixing of civilian and military activities. Narrative warfare involves reinforcing the
legitimacy of historic rights within the ten-dash line through ancient maps and academic
research (McLaughlin, 2022). Legal warfare includes reinterpreting international and
customary law, such as asserting maritime delimitation rights through land reclamation
and artificial island construction. China has also enacted domestic laws with
extraterritorial implications—such as the Coast Guard Law, amended Maritime Traffic
Safety Law, and the Outline of Military Non-War Military Operations—to expand the scope
and scale of its forces’ overseas activities. Following the promulgation of its Coast Guard
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Law in 2021, which explicitly listed “safeguarding national sovereignty” as a purpose and
authorized the use of weapons against foreign infringements, China further expanded its
legal basis for enforcement. The law also grants the Coast Guard authority to expel or
tow away foreign military or government vessels. In May 2024, the CCG issued
Administrative Order No. 3, regulating enforcement procedures, thereby extending
domestic legislation into the international domain.
Specifically, China’s Coast Guard Law and Administrative Order No. 3 authorize coast
guard patrols and boarding inspections to coerce other states, preventing them from
exercising their sovereign rights and enabling China to conduct governmental jurisdiction
warfare. This has resulted in numerous collisions between CCG vessels and fishing boats
from other countries, such as Vietnam. The CCG also frequently patrols near the natural
gas fields located within disputed EEZs of countries such as Malaysia, Vietnam, and
Indonesia. In particular, confrontations with Vietnam are common in the vicinity of the
Vanguard Bank oil field (Sebastian, 2021). Psychological warfare includes covert
command and funding activities to infiltrate foreign government agencies and sponsoring
large networks of online trolls (“Little Pinks”) and hackers targeting government and
private institutions. For example, on July 29, 2016, Chinese hackers infiltrated Vietnam’s
major international airports and broadcast messages declaring “the South China Sea
belongs to China” (Hsu, 2016).
Finally, mixing civilian and military activities involves deploying large numbers of fishing
vessels acting as maritime militia. Equipped with advanced satellite communications and
water cannons, they surround disputed territories to demonstrate China’s sovereignty.
Such an action represents a gray-zone strategy that most closely resembles military
operations.
3
This tactic dates back to 1973 during the Paracel Islands dispute, when
China dispatched armed “fishermen” (maritime militia) to land on the islands, eventually
prompting naval clashes with South Vietnam (Xinhua News, 2017). This tactic has since
evolved into what O’Rourke (2019) terms the “Cabbage Strategy,” which involves
encircling disputed areas with layers of fishing vessels, coast guard ships, and naval
warships to assert sovereignty claims and enable occupation without direct conflict.
The most successful example is Scarborough Shoal, where China established de facto
control by deploying fishing vessels, then fisheries patrol ships under the pretext of
protecting fishermen, ultimately blocking Philippine control (Bau, Tso, & Liao, 2014).
China used similar tactics against Philippine resupply missions to the BRP Sierra Madre
grounded at Second Thomas Shoal (Ren’ai Jiao). China initially deployed maritime militia
vessels to surround the area, making it difficult for the Philippines to conduct resupply
operations. This was followed by Chinese coast guard ships coercing Philippine
government vessels to alter their course, with the apparent aim of forcing the Filipino
troops stationed on the Sierra Madre to abandon the ship. In 2024, the CCG announced
that it would impose control measures on Philippine vessels it deemed to have “illegally
intruded” into the waters surrounding Second Thomas Shoal. The Philippine Coast Guard
subsequently accused the CCG of damaging its supply vessels. On June 17, armed CCG
personnel boarded a Philippine Navy resupply boat and injured Filipino naval personnel.
Tensions between the two sides escalated until July 2, when Chinese and Philippine
3
Therefore, in 2019, the United States declared that it would regard maritime militia, coast guard, and navy
forces as equivalent in its operational considerations (Sevastopulo and Hille, 2019).“
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foreign ministers convened the 9th meeting of the Bilateral Consultation Mechanism on
the South China Sea (BCM), bringing about a temporary halt to the confrontation.
Overall, China’s main objective in the South China Sea is to expand its sovereign rights
and influence rather than physically occupy other claimants’ territories. Although the
claimant states in the South China Sea are individually weaker than China, their large
number means that any rash use of military force by China could potentially trigger the
formation of an anti-China coalition. The use of gray-zone strategies has thus become
China’s preferred approach in this region (Zhang, 2019). These tactics provoke less initial
controversy and enable China to justify its actions incrementally, altering the status quo
and international norms through a salami-slicing approach. Unlike the U.S., which
upholds international law and a rules-based order as the foundation of South China Sea
governance, China seeks to construct an order based on sovereignty principles and
negotiations, thereby reshaping existing power dynamics. The contest for regional order
between China and the United States thus continues.
East China Sea: New Normal
Relative to the South China Sea, the East China Sea has delimitation disputes involving
only China, South Korea, Japan, and Taiwan (Park, 1975, 27). In 1974, Japan and South
Korea signed two agreements concerning the continental shelf in areas where their
maritime claims overlapped (Makoto and Becker-Weinberg, 2024). In 2001, China and
South Korea signed the China–South Korea Fisheries Agreement, which established
provisional measure zones in the Yellow Sea to be jointly managed by both parties.
Although China and Japan reached the 2008 “Consensus on principles of the China-Japan
East China Sea issue,” which set out a cooperative framework for delimiting their
Exclusive Economic Zones and for oil and gas development, the agreement lacked
implementing details and thus has remained largely ineffective.
China’s gray zone tactics in the East China Sea similarly involves allowing large numbers
of Chinese fishing vessels to operate there, thereby expanding the scope of China’s
claimed fishing grounds, even at the risk of colliding with JCG vessels. For example, in
the 2010 Minjinyu 5179 incident, the Chinese trawler Minjinyu 5179 collided with
Japanese patrol ships and was subsequently detained by Japan. The incident ultimately
ended with Japan expressing regret, which was regarded as a victory for China’s claim
of legitimate fishing rights (Bau, Tso and Liao, 2014). However, unlike its gray-zone
tactics in the South China Sea, China has not employed large numbers of maritime militia
vessels to encircle the Diaoyu/Senkaku Islands or to obstruct Japan’s exercise of
administrative jurisdiction over them. Instead, it has relied on governmental jurisdiction
warfare. In addition, China has justified its sovereignty safeguarding actions in the East
China Sea by asserting sovereignty over the Diaoyu/Senkaku Islands and by invoking
arguments such as the natural prolongation principle in its continental shelf delimitation
claims.
Another gray-zone tactic that China employs in the East China Sea is governmental
jurisdiction warfare, which is supported by legal warfare with extraterritorial effects
through domestic legislation, such as the aforementioned Coast Guard Law and
Administrative Order No. 3. Since Japan nationalized the Diaoyu/Senkaku Islands in
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2012, CCG vessels have increased the frequency of their patrols in the East China Sea,
even entering the territorial waters surrounding the Diaoyu/Senkaku Islands, as shown
in Figure 1 (Ministry of Foreign Affairs of Japan, 2025).
Figure 1. Trends in CCG and Other Vessels in the Waters Surrounding the Diaoyu/Senkaku
Islands
Source: Ministry of Foreign Affairs of Japan. 2025,
https://www.mofa.go.jp/region/page23e_000021.html
Despite Japan’s protests and JCG efforts to drive them away, Chinese incursions have
increased in both number and duration (Pajon, 2017).. Since November 2023, CCG has
published statements on its official website, including titles such as “The China Coast
Guard has lawfully managed and controlled Japanese vessels illegally entering the
territorial waters of our Diaoyu/Senkaku Islands,” asserting that its actions constitute
legitimate law enforcement against Japanese vessels. These statements declare, “The
Diaoyu/Senkaku Islands and their affiliated islands are China’s inherent territory…We
urge Japan to immediately stop all illegal activities in these waters (China Coast Guard,
2023)” reiterating China’s claim of sovereignty over the Diaoyu/Senkaku Islands and
demanding that Japan cease entering what it considers its territorial waters. In June
2024, four armed Chinese Coast Guard vessels entered the islands’ territorial waters,
prompting Tokyo to lodge a strong protest demanding their immediate withdrawal
(Reuters, 2024). Later, the massive CCG 2901 vessel, one of the world’s largest maritime
law enforcement ships, sailed around the Diaoyu/Senkaku Islands (Yomiuri Shimbun,
2024). In March 2025, the JCG reported that CCG vessels remained in the islands’
territorial waters for a record 92 hours and 8 minutes (Kosuke, 2025). China’s maritime
law enforcement operations near the Diaoyu/Senkaku Islands have grown progressively
more assertive.
In 2025, China erected a sea structure in the Yellow Sea within an area of overlapping
claims with South Korea, off the Korean Peninsula’s west coast. Although China claimed
it was fish-farming equipment, it prompted concern from South Korea (Yim, 2025). China
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has employed similar tactics in the East China Sea, prompting Japanese demands for
explanation. Although China claims such structures are unrelated to sovereignty, they
are viewed as potential gray-zone strategy tools, given their possible future use for radar
systems or interference with foreign vessels’ navigation.
China has employed gray-zone tactics in the East China Sea, including narrative warfare,
legal warfare, and contests over governmental jurisdiction, to gradually undermine
Japan’s previously unchallenged dominance and to create the perception of joint
administration with Japan. This strategy has eroded Japan’s exclusive administrative
control, establishing what has been termed a “new normal,” although in practice Japan
retains effective control over the Diaoyu/Senkaku Islands.
4
Overall, the so-called “new
normal” in the East China Sea does not represent a stable state but rather a dynamic
process in which China continues to strengthen its presence. Even the previously calm
Yellow Sea has begun to experience ripples as a result. Indeed, China’s gray-zone
strategies are being used to gradually alter the status quo.
Taiwan Strait: Internalization
The Taiwan Strait issue is fundamentally different in nature from China’s disputes in the
East and South China Seas. Since the establishment of the People’s Republic of China
(PRC) on October 1, 1949, the PRC and the Republic of China (ROC) in Taiwan have
existed as two separate governing authorities. While China has exercised actual control
only over the mainland, it has never abandoned its intention to unify Taiwan. In other
words, China has consistently maintained that Taiwan is an integral part of its territory.
Beyond military exercises intended to intimidate Taiwan, China disseminates
disinformation and seeks domestic proxies within Taiwan to directly influence public
perceptions, thereby creating panic or achieving deterrent effects. For example, during
U.S. House Speaker Nancy Pelosi’s visit to Taiwan in 2022, numerous Taiwanese
government and private sector websites were attacked or rendered inoperable.
Additionally, screens at Taiwan Railways stations and convenience stores displayed
statements insulting Pelosi (Tsai, 2022). Admittedly, such tactics are unlikely to yield
immediate results during peacetime. However, once both sides enter a period of
heightened tension or confrontation, these strategies could achieve what Sun Tzu
described as defeating the enemy’s will to resist before actual combat begins. Moreover,
China may actively co-opt pro-China individuals in Taiwan to disseminate information
detrimental to the Taiwanese government, thereby undermining internal cohesion.
Secondly, China has employed narrative warfare to emphasize the inevitability of Cross-
Strait unification. It highlights the 1943 Cairo Declaration and the 1945 Potsdam
Declaration, both of which stipulated that Taiwan would be returned to China, arguing
4
According to interviews conducted by the author in June 2024 with scholars at the National Institute for
Defense Studies, Tokyo University and Keio University, the Japanese government has integrated the real-time
communication systems of the Japan Maritime Self-Defense Force (JMSDF) and the JCG, enabling the Coast
Guard to receive timely intelligence regarding Chinese vessels. However, they also noted that if CCG ships
refuse to leave, the JCG can do no more than monitor and shadow them, as taking further action could provoke
a dispute. The scholars pointed out two main reasons for this dilemma: first, Japan lacks a plan for 24-hour
continuous patrols; and second, the situation is still considered a law enforcement matter, thus not warranting
U.S. involvement.
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that the PRC, as the successor state, inherits this sovereignty, rendering the Taiwan issue
an internal matter. However, internationally, countries such as the U.S., the United
Kingdom, and Japan maintain that the 1951 San Francisco Peace Treaty, which formally
ended World War II, did not explicitly state that Taiwan should be returned to China. In
recent years, China has further equated United Nations General Assembly Resolution
2758—which granted the PRC China’s seat at the UN—with its “One China Principle,”
underscoring its narrative that both sides of the Strait belong to one China. Moreover,
China asserts sovereignty over Taiwan and treats the One China Principle as a
precondition for diplomatic relations, requiring other countries to acknowledge that
“Taiwan is part of China.” Domestically, it has enacted the Anti-Secession Law, the
National Security Law, and the Counter-Espionage Law, defining support for Taiwan
independence as an act that endangers national security. Such measures imply an
expansion of extraterritorial jurisdiction, signaling not only legal warfare but also
potential enforcement actions constituting governmental jurisdiction warfare.
Following the “Kinmen 0214 Incident” in 2024, CCG vessels began driving away and
attempting to board Taiwanese fishing boats operating within restricted waters
designated by Taiwan. China also denied the existence of the long-standing tacit
understanding regarding the median line in the Taiwan Strait. CCG ships, military aircraft,
and naval vessels have repeatedly crossed this median line. Furthermore, in 2022 China
conducted encirclement exercises around Taiwan to warn against its decision to host U.S.
House Speaker Pelosi, with the designated exercise zones even including a small portion
of Japan’s claimed EEZ. In 2024, it carried out Joint Sword–2024A and 2024B exercises,
followed by multiple encirclement drills starting in April 2025. The areas designated for
these exercises have gradually moved closer to Taiwan’s declared territorial waters,
demonstrating China’s intent to assert its control and jurisdictional authority in the
surrounding areas.
Overall, the gray-zone tactics China employs in the Taiwan Strait are aimed at
internalizing the Strait as China’s inland waters and domesticating Taiwan such as
narratives warfare, legal warfare, and psychological warfare. Since the Kinmen 0214
incident, although China has deployed more coast guard vessels to patrol and has
increasingly crossed the median line of the Taiwan Strait—thereby undermining the
previous tacit understanding of separate administrative control over respective waters—
it has not yet carried out actual boarding inspections or law enforcement operations.
Regarding the Taiwan Strait, China primarily uses military means to demonstrate its
position. Notably, in June 2025, China’s aircraft carriers Liaoning and Shandong
conducted an unprecedented simultaneous deployment into the Western Pacific, crossing
the Second Island Chain. This demonstrated China’s potential for long-range operations
and served to shift international attention from the Taiwan Strait to the western Pacific.
Comparisons of the Three Cases
Based on the comparison of the above three cases, it is evident that due to differences
in objectives and the number and strength of neighboring countries, China has adopted
different approaches in its use of gray-zone strategies. Two key characteristics can be
summarized.
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First, the frequency and type of gray-zone strategies that China employs in the South
China Sea, East China Sea, and Taiwan Strait vary according to its strategic objectives
in each region. The greater level of the impacts on sovereignty, the less frequently gray-
zone strategies are employed, and the more likely China is to resort to military means to
signal its concern in the area. The greater the impact on sovereignty, the less frequently
gray-zone strategies are employed, and the more likely China is to resort to military
means to signal its concerns. That is, China tends to employ military means in response
to issues it perceives as serious violations of its sovereignty, while adopting gray-zone
strategies for situations it views as involving lesser infringements. In the Taiwan Strait,
China relies less on gray-zone strategies and more on quasi-military actions, such as
deploying over 500 missiles aimed at Taiwan, regularly sending military aircraft and naval
vessels across the median line, and conducting military exercises that gradually approach
Taiwan’s territorial waters. In the East China Sea, the CCG accompanied by military
vessels is the primary tool used to intervene in the status quo. In contrast, in the South
China Sea, gray-zone tactics are effective for harassing other countries aiming to
gradually change the status quo, while military means may provoke stronger resentment
and lead to conflict, making them less preferable.
Specifically, China’s objectives in the South China Sea are twofold: to assert economic
sovereign rights and to establish an alternative order to the U.S.-led liberal international
order. Physical occupation of the entire South China Sea is not its primary goal. Moreover,
its opponents in the region are relatively weak and fragmented; none can individually
challenge China’s power, though their collective number exceeds that of China’s
opponents in the East China Sea and Taiwan Strait. To avoid provoking excessive
reactions and escalation into military conflict, China is more inclined to employ gray-zone
strategies. In the East China Sea, China’s goals include preserving its sovereign rights
and asserting sovereignty over the Diaoyu/Senkaku Islands. However, its opponent,
Japan, is not weak and benefits from the protection of the U.S.-Japan security treaty.
Hence, to avoid war or confrontation with the U.S., gray-zone strategies are preferred,
but more severe levels are employed to signal its serious concerns over the
Diaoyu/Senkaku Islands. Lastly, China’s goal in the Taiwan Strait is unification with
Taiwan, for which it has never ruled out the use of force. Thus, gray-zone strategies are
less emphasized, as China is willing to demonstrate its resolve to avoid losing Taiwan.
Secondly, regarding the likelihood of triggering military conflicts, the five gray-zone
tactics identified in this paper can be ranked as shown in Figure 1. The greater the impact
on sovereignty, the more China tends to employ gray-zone tactics with higher risks of
provoking conflict. In contrast, when sovereignty is less affected, it prefers gray-zone
tactics that are less likely to escalate into war.
Figure 1. Severity of Gray-Zone Tactics
Source: the author. Note: Dual activities refer to the mixing of civilian and military activities.
Less likely Most likely
Narrative psychological legal dual activities governmental jurisdiction
warfare warfare warfare warfare
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Given that China’s objective in the Taiwan Strait is to achieve sovereignty over Taiwan,
it remains prepared for the possibility of war, even if it does not anticipate immediate
conflict, and thus does not hesitate to employ gray-zone tactics carrying a high risk of
escalation. In the East China Sea, which also involves sovereignty disputes, China prefers
employing high-intensity gray-zone tactics but seeks to avoid provoking military conflict
due to the presence of the U.S.-Japan alliance. In the South China Sea, where multiple
rival claimant states exist, China tends to employ gray-zone tactics that are less likely to
provoke military conflict. By doing so, it allows different countries to interpret its actions
in varying ways, increasing the likelihood of avoiding war (Liao, 2021, pp. 33–35).
Conclusions
Gray-zone strategies are not a newly emergent phenomenon. However, in recent years,
they have re-emerged on the international stage due to Russia’s annexation of Crimea
and China’s increasingly assertive and aggressive behaviors in the Indo-Pacific region.
Nonetheless, including tactics with explicit military characteristics under the definition of
gray-zone strategies risks obscuring the significance of non-military means within gray-
zone operations, as well as their fundamental objective of avoiding open warfare.
Therefore, this paper redefines gray-zone strategies as a country's attempt to change or
influence another country's sovereignty rights or policies through governmental or non-
governmental actions, thereby redefining mutual strategic interests. Based on a review
of the literature, this study identifies five types of non-military gray-zone tactics, ranked
according to their potential to trigger military conflict: narrative warfare, psychological
warfare, legal warfare, mixing of civilian and military activities, and governmental
jurisdiction warfare.
Based on this analysis, this paper examines China’s use of gray-zone tactics in the South
China Sea, East China Sea, and Taiwan Strait, and identifies two key characteristics.
First, China tends to employ military means in response to issues it perceives as serious
violations of its sovereignty, while adopting gray-zone strategies in situations it views as
involving lesser infringements. Second, the greater the impact on its sovereignty, the
more China tends to employ gray-zone tactics that carry a higher risk of provoking
conflict. In contrast, when sovereignty is less affected, it prefers gray-zone tactics that
are less likely to escalate into war. These two characteristics can be attributed to the
different objectives China pursues in the South China Sea, East China Sea, and Taiwan
Strait, as well as variations in the nature and capabilities of its opponents. Consequently,
the effects produced by gray-zone strategies in these three regions also differ.
In the South China Sea, China’s gray-zone strategies have produced evolutionary impacts
on the international order. Although these tactics are non-military in nature, they
implicitly signal the possibility of subsequent military action. Through such psychological
deterrence aimed at undermining the adversary’s will to resist, the actor can gradually
alter the status quo in a 'salami-slicing' manner. For instance, despite winning the 2016
arbitration case on the South China Sea, the Philippines lost control of Scarborough Shoal
due to China’s gray-zone tactics. Yet former President Duterte publicly stated that the
Philippines could not and would not confront China unless it meant going to war. In this
sense, gray-zone strategies function as tools of coercive deterrence, seeking to replace
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the U.S.-led liberal international order based on the rule of law with a China-led order
grounded merely in rule by law.
It is noteworthy that in all three regions—the South China Sea, East China Sea, and
Taiwan Strait—China’s use of gray-zone strategies is underpinned by its expanding
military capabilities. In the South China Sea, China has enhanced its effective control
over disputed features through island-building, administrative measures, and resource
extraction, using these as a foundation to actively reshape regional order in competition
with the U.S.-led liberal international order, shifting the power configuration toward a
new equilibrium. In the East China Sea, although a “new normal” of joint management
between China and Japan appears to have emerged, this arrangement is neither
symmetrical nor static. For instance, Japan Coast Guard (JCG) patrol vessels are not
equipped with heavy weaponry such as cannons, whereas CCG vessels are, meaning the
seemingly stable situation could tilt further in China’s favor at any time. In the Taiwan
Strait, the effects of China’s gray-zone strategies are felt more as psychological
deterrence against the Taiwanese public, as well as in establishing both the capability
and legitimacy to exclude international intervention.
In light of this, while countries must handle and respond to China’s use of gray-zone
tactics with caution, greater attention should be paid to the underlying expansion of
China’s military capabilities and influence. When confronted with these near-harassment
gray-zone tactics, countries should also consider responding with asymmetric or lower-
cost measures that nonetheless are of great concern to China, such as increasing
exchanges with Taiwan or enhancing Taiwan’s international status. If such actions are
taken by individual states, they may provoke Chinese retaliation. However, if countries
act collectively to strengthen their relations with Taiwan, even minor progress could be
enough to significantly unsettle China and shift its original strategic focus. In other words,
rather than allowing China to address the South China Sea, East China Sea, and Taiwan
Strait separately through distinct gray-zone tactics, a coordinated approach that targets
China’s vulnerabilities could prove far more effective in countering its use of gray-zone
strategies.
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