India, Japan, and Indonesia as the architectural core of counter-encirclement.
The geopolitical centre of gravity has firmly settled within the waters of the Indo-Pacific. This vast maritime domain, which anchors global trade routes and holds immense resource wealth, has become the primary arena for intense systemic rivalry. At the centre of this tension is China’s assertive expansionism, structurally manifested through its “String of Pearls” strategy. By developing a network of military, commercial, and logistical nodes across the Indian Ocean rim—stretching from Gwadar in Pakistan and Hambantota in Sri Lanka to Kyaukphyu in Myanmar—Beijing has sought to engineer a comprehensive maritime encirclement of India while securing unchecked access to critical chokepoints. This expansion is paired with aggressive grey-zone operations in the East and South China Seas, threatening the maritime sovereignty of littoral states.
Historically, the regional response to this challenge relied on broad, loosely defined multilateral frameworks or exclusive, Western-led alliances. But the emerging trilateral dynamic between India, Japan, and Indonesia represents a highly significant strategic alignment in the region. Unlike traditional security architectures, this trio brings together three major Asian democracies that possess distinct, overlapping geopolitical identities: India as the net security provider of the Indian Ocean, Japan as the technological and economic anchor of the North Pacific, and Indonesia as the archipelagic gatekeeper of the vital sea lines of communication connecting the two oceans.
INDIA-INDONESIA: KINETIC HARD POWER AT THE ARCHIPELAGIC GATES
The bilateral relationship between India and Indonesia forms the southern and western anchor of this strategic triangle. For decades, ties between New Delhi and Jakarta were defined by shared cultural history and non-aligned diplomacy, which rarely translated into hard security cooperation. However, as Beijing’s maritime assertiveness increasingly encroached upon Indonesia’s exclusive economic zone around the Natuna Islands and threatened India’s oceanic approaches, both nations recognized the need for an upgraded defence posture. Under India’s “Act East” policy and Indonesia’s “Optimum Essential Force” modernization strategy, this partnership has rapidly transitioned into a high-stakes defence-industrial alliance.
This strategic evolution reached a historic peak in July 2026 during Prime Minister Narendra Modi’s state visit to Jakarta. In a series of landmark agreements with Indonesian President Prabowo Subianto, India and Indonesia finalized a comprehensive defence export package valued at over $600 million. The crown jewel of this agreement is an official contract for India to supply Indonesia with advanced batteries of the BrahMos supersonic cruise missile system, alongside a concurrent pact for indigenous Astra Mk-1 beyond-visual-range air-to-air missiles.
The introduction of the BrahMos system into Indonesia’s coastal defence infrastructure alters the tactical balance in the region’s primary maritime chokepoints. Travelling at speeds up to Mach 3.0, the BrahMos is exceptionally difficult for modern naval air defences to intercept. By deploying these sea-skimming, anti-ship missiles along the Malacca, Sunda, and Lombok straits, Indonesia gains a potent Anti-Access/Area Denial () capability. This capability directly addresses China’s “Malacca Dilemma”—its acute vulnerability to having its primary energy supply lines cut off in a crisis. With Indian-supplied missiles guarding the archipelagic gates and an Indonesian Liaison Officer integrated into India’s Information Fusion Centre for the Indian Ocean Region, the two nations have effectively turned China’s primary economic highway into a highly monitored, heavily armed corridor.
This kinetic deterrence is reinforced by forward-deployed infrastructure cooperation at the Port of Sabang, situated on the northern tip of Sumatra. Located just 90 nautical miles from India’s tri-service military command in the Andaman and Nicobar Islands, Sabang occupies a vital position at the western mouth of the Malacca Strait. India’s active investments in developing Sabang into a deep-sea port and naval logistics hub create an interlocking defensive canopy. This infrastructure synergy grants the Indian Navy critical maintenance and logistical access right at the gateway to the Pacific, enabling seamless joint patrols and real-time maritime domain awareness operations with the Indonesian Navy.
INDIA-JAPAN ALLIANCE: ELECTROMAGNETIC SHIELDING, TECHNOLOGICAL CO-DEVELOPMENT
While the Indo-Indonesian track provides the heavy kinetic assets to secure the region’s southern chokepoints, the northern axis of the triangle, the India-Japan partnership, delivers the advanced technological capabilities and electronic warfare systems needed to withstand modern peer-competitor conflict. The relationship between New Delhi and Tokyo has long been considered the most stable bilateral vector in the Indo-Pacific, anchored by their shared commitment to a “Free and Open Indo-Pacific” (FOIP). However, the alliance entered a new era in July 2026, shifting from diplomatic alignment to deep defence-industrial integration.
At the 16th India-Japan Annual Summit in New Delhi, Prime Minister Narendra Modi and Japanese Prime Minister Sanae Takaichi signed a historic agreement launching their first-ever military co-development project: the UNICORN (Unified Complex Radio Antenna) mast for the Indian Navy’s next-generation warships. Developed by Japan’s NEC Corporation, Sampa Kogyo, and Yokohama Rubber, the UNICORN (or NORA-50) system represents a significant leap in electronic warfare and naval stealth.
Unlike traditional warship masts that feature cluttered arrays of exposed communication antennas, radar dishes, and electronic support measures—which create a large radar cross-section—UNICORN consolidates all electronic warfare, tactical air navigation, Link-16, and multi-band communication arrays inside a single, smooth composite radome. This design slashes a vessel’s radar signature, making it much more difficult for an adversary’s over-the-horizon radars and satellite tracking networks to detect, track, and classify.
Under this pact, India’s state-run Bharat Electronics Limited (BEL) will manufacture and integrate these advanced masts locally, combining Japanese design with India’s expanding domestic defence production. This co-development model is highly significant. By integrating Japanese stealth engineering into its surface fleet, the Indian Navy drastically reduces its vulnerability to China’s long-range anti-ship ballistic and cruise missile networks.
Furthermore, this deal marks a notable evolution in Japan’s strategic posture. By relaxing its strict, self-imposed post-war defence export restrictions, Tokyo is actively leveraging its world-class electronics and materials science sectors to arm its strategic partners. This ensures that democratic navies operating in the contested waters of the Indo-Pacific retain a critical technological and electromagnetic edge.
JAPAN-INDONESIA VECTOR: CAPACITY BUILDING AND ECONOMIC RESILIENCE
The third side of the triangle, connecting Tokyo and Jakarta, bridges the gap between high-end security assistance and regional capacity building. Indonesia’s expansive archipelagic geography makes it highly vulnerable to illegal maritime incursions, resource exploitation, and grey-zone assertiveness, particularly from Chinese fishing fleets and coast guard vessels near the Natuna Sea. Recognizing that Indonesia lacks the capital to independently modernize its maritime security forces overnight, Japan has stepped in as a critical partner in capacity building and economic resilience.
Through its Official Security Assistance (OSA) framework and dedicated maritime aid programs, Japan has consistently provided the Indonesian Coast Guard (Bakamla) with large-scale patrol vessels, advanced radar equipment, and comprehensive maritime surveillance training. This targeted assistance enables Jakarta to maintain a persistent, visible regulatory and security presence throughout its vast maritime domain without draining its core naval combat resources.
Equally important is the economic dimension of the Japan-Indonesia partnership, which serves as a powerful alternative to China’s Belt and Road Initiative (BRI). Beijing has frequently used infrastructure debt as a tool of geopolitical coercion, a tactic that successfully delivered ports like Hambantota into Chinese hands. To prevent a similar vulnerability within the Indonesian archipelago, Japan has directed high-quality, transparent infrastructure investments into Indonesia’s strategic ports, transit networks, and digital infrastructure. Furthermore, as part of the broader trilateral push for supply chain resilience, Japan and India have partnered with Indonesia to invest heavily in the local processing of critical minerals.
Indonesia possesses some of the world’s largest reserves of nickel, copper, and bauxite—materials that are absolutely vital for modern defence electronics, aerospace applications, and green energy technology. By financing advanced processing facilities within Indonesia, Japan and India are helping Jakarta move up the value chain while establishing secure, independent supply lines for these critical resources. This economic cooperation helps safeguard Southeast Asia’s industrial base from coercive monopolies, ensuring the region’s long-term autonomy.
COMBINED TRILATERAL SYNERGY: DISMANTLING THE STRING OF PEARLS
When these three bilateral relationships converge into a single, coordinated strategic architecture, they form a resilient mechanism that fundamentally deconstructs the logic of China’s String of Pearls encirclement. The success of Beijing’s maritime containment strategy depends entirely on the assumption that the People’s Liberation Army Navy (PLAN) can project power across the Indian Ocean rim completely unimpeded, relying on its forward bases in Pakistan, Sri Lanka, and Myanmar to box India in.
The India-Japan-Indonesia trilateral completely upends this geographic equation. By dividing strategic responsibilities according to their unique national strengths, the three nations form a highly capable security network.
THE TRIO: INDIA, JAPAN AND INDONESIA
In a geopolitical crisis, this combined capability acts as a formidable maritime barrier. If China attempts to deploy naval forces out of its forward bases in the Indian Ocean, those forces must be reinforced and resupplied via sea lines of communication running back through the Indonesian straits. The trilateral network ensures that these chokepoints can be securely monitored or completely closed off.
Supported by Japanese stealth tech on Indian warships and Indian supersonic cruise missiles on Indonesian shores, the three partners possess the collective capability to disrupt hostile transit. Rather than successfully encircling India, China’s forward bases west of Southeast Asia would risk being isolated, trapped behind a trilateral wall capable of severing their lines of reinforcement and logistics at a moment’s notice.
MULTIPOLAR ANCHOR FOR INDO-PACIFIC
The synchronised breakthroughs of mid-2026, highlighted by Indonesia’s landmark BrahMos contract and the historic India-Japan UNICORN co-development pact, represent a major turning point in the security dynamics of the Indo-Pacific. By binding their security architectures together through defence technology transfers, infrastructure coordination, and supply chain resilience, India, Japan, and Indonesia are building a stable, distributed balance of power.
This trilateral synergy ensures that the vital sea lanes connecting the Indian and Pacific Oceans cannot be dominated by a single power, providing a resilient anchor for a free, open, and truly multipolar regional order.
*Hindol Sengupta is Professor of International Relations at O.P. Jindal Global University.
