# Grey-Zone Drills
> Military and paramilitary exercises designed to coerce adversaries below the threshold of open war, most extensively practiced by China against Taiwan, Japan, and the South China Sea.

**Meta:** type: reference · date: 2026-07-03 · heads:  · 4 takes · 4 lenses · 2 regions

## What it is

Grey-zone drills are military and paramilitary exercises designed to rehearse coercive operations that fall below the threshold that would trigger a conventional military response or invoke formal alliance commitments. Unlike standard war games, they combine regular military forces, coast-guard vessels, maritime militia, cyber units, and information operations to create deliberate ambiguity about intent and attribution. The US DNI's updated Intelligence Community Gray Zone Lexicon, published July 2024, defines the grey zone as the "competitive space between routine statecraft and open warfare." Actors conducting these drills seek to shift facts on the ground, erode adversary resolve, and avoid clear-cut acts of force that would justify a formal military reply.

The principal practitioners as of mid-2026 are China (targeting Taiwan, Japan's Senkaku Islands, and South China Sea claimants), Russia (targeting NATO's eastern flank through shadow-fleet harassment, Baltic airspace probing, and sabotage attributed to GRU units), and North Korea (calibrated missile tests and oil-smuggling runs designed to impose costs without triggering collective-defence obligations).

## History

The concept solidified in US strategic literature after Russia's 2014 annexation of Crimea and China's island-building campaign in the South China Sea demonstrated that great-power rivals had moved below the deterrence threshold of conventional military tools. A RAND Corporation study formally defined the grey zone as an "operational space between peace and war" in which coercive actions change facts on the ground while "blurring the line between military and non-military actions." The UK Parliament's Defence Select Committee reached a parallel conclusion in its own inquiry, finding that both Russia and China had developed grey-zone capabilities specifically calibrated to exploit gaps in NATO and allied legal authorities.

China's grey-zone campaign against Taiwan began in earnest after the 1996 Taiwan Strait Crisis, when US carrier battle groups deterred PLA action and Beijing resolved to develop tools harder to counter with carriers. The PLA's August 2022 exercises, triggered by then-US House Speaker Nancy Pelosi's Taipei visit, marked a doctrinal shift: for the first time the PLA established de-facto exclusion zones that Taiwan and its partners treated as a new permanent baseline rather than a one-off provocation.

## Current state

China's campaign against Taiwan is the most data-dense grey-zone as of mid-2026. PLA aircraft entered Taiwan's air-defense identification zone more than 3,700 times in 2025, the highest annual total on record. The Chinese coast guard spent 335 consecutive days patrolling waters around Japan's Senkaku Islands in 2025, shattering the previous record of 215 days. "Justice Mission 2025," the sixth major PLA exercise simulating a Taiwan blockade since 2022, closed inside the perimeter of previous exercises (see [중국 항모 전단, 5일 봉쇄 예행 연습 마무리로 대만 해협 통과](/ko/n/china-taiwan-blockade-rehearsal-jun25) and [PLA 항모 푸젠함, 미국 동맹국 발리언트 실드 훈련 중 12월 이후 처음으로 대만해협 통과](/ko/n/pla-fujian-taiwan-strait-jun22)). China's grey-zone fleet operates as an ecosystem: coast-guard vessels, maritime militia fishing boats, sand dredgers, and opaquely owned cargo ships, all used to harass and probe while stopping short of armed conflict.

Allied counter-pressure has intensified. The US, Japan, Australia, and the Philippines mounted coordinated coast-guard patrols in June 2024 (see [미국·영국·프랑스·독일, 대만 동쪽 중국 해경 순찰에 대한 사상 첫 공동 경고문 발표](/ko/n/taiwan-four-power-coast-guard-jun24)). Taiwan has reframed its response to prioritise cost-imposition, including detaining vessels implicated in undersea cable sabotage and increasing transparency about Chinese incursions to delegitimise Beijing's narratives.

## Relationships

Grey-zone drills are the operational expression of the rivalries tracked in [Taiwan Strait](/ko/n/taiwan-strait-dossier): they test alliance credibility, drive demand for counter-measures such as electronic warfare and AI-enabled attribution, and feed into the deterrence debates rehearsed in [대만, 중국의 해상 강압 시나리오 상정 첫 공개 도상훈련 실시](/ko/n/taiwan-coercion-tabletop-jun26). Because grey-zone activity is designed to remain below the formal threshold of conflict, it consistently outpaces the legal frameworks and rules of engagement that defenders rely on. RUSI's March 2025 analysis found Taiwan's core vulnerability is diplomatic isolation, which discourages escalatory responses and makes coalition-building with other grey-zone targets the most actionable path.

## What to watch

- Whether the PLA's 2026 exercises expand beyond the normalised perimeter that "Justice Mission 2025" established around Taiwan, or extend into the Philippine Sea.
- US Indo-Pacific Command's response to China's record Senkaku coast-guard presence as Japan invokes its expanded self-defence authorities under the 2022 National Security Strategy.
- Taiwan's progress on RUSI's recommendation to build a regional grey-zone coalition sharing attribution intelligence, with the Philippines, Japan, and Australia as the core.
- Whether China's 2021 coast-guard law, authorising lethal force in claimed waters, is invoked against a US or allied vessel in the Senkaku or Spratly theatres.

## Regional takes (batched by bias / lens)

### official record
- **US Director of National Intelligence: IC Gray Zone Lexicon (July 2024)** (United States, en) — Unclassified July 2024 update to the US Intelligence Community's grey-zone terminology, defining the grey zone as the competitive space between routine statecraft and open warfare and cataloguing the activities states use within it.
  Source: https://www.dni.gov/files/ODNI/documents/assessments/NIC-Unclassified-Updated-IC-Gray-Zone-Lexicon-July2024.pdf

### official parliamentary record
- **UK Parliament Defence Select Committee: Defence in the Grey Zone** (United Kingdom, en) — UK House of Commons Defence Committee report examining grey-zone threats from Russia and China to UK and allied interests, with recommendations on response capacity, legal authorities, and attribution capabilities.
  Source: https://publications.parliament.uk/pa/cm5901/cmselect/cmdfence/405/report.html

### US defence policy research
- **RAND Corporation: Competition in the Gray Zone (RRA594-1)** (United States, en) — Foundational RAND study defining grey-zone competition and mapping China's coercion against US allies and partners across the Indo-Pacific, with options for counter-pressure below the threshold of armed conflict.
  Source: https://www.rand.org/pubs/research_reports/RRA594-1.html

### UK security analysis
- **Royal United Services Institute: Taiwan's Evolving Response to China's Grey Zone Actions** (United Kingdom, en) — March 2025 RUSI policy brief by Dr Philip Shetler-Jones cataloguing China's grey-zone toolkit against Taiwan, assessing Taiwan's vulnerabilities, and recommending a coalition of grey-zone victims to share attribution intelligence and impose costs.
  Source: https://www.rusi.org/explore-our-research/publications/policy-briefs/taiwans-evolving-response-chinas-grey-zone-actions

## Across the graph
- Related: [[china-taiwan-blockade-rehearsal-jun25]], [[taiwan-coercion-tabletop-jun26]], [[taiwan-strait-dossier]], [[pla-fujian-taiwan-strait-jun22]], [[taiwan-four-power-coast-guard-jun24]]
- Entities: Grey Zone Drills, China, Taiwan, Pla, Place:taiwan Strait, South China Sea

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