Multidimensional Deterrence: Analysis of the PLA's Comprehensive Countermeasures in the South China Sea During the "Shoulder to Shoulder 2026" Exercise

In late April to early May 2026, the Philippines and the United States held the largest "Shoulder-to-Shoulder" (Balikatan) joint military exercise to date, with approximately 17,000 troops participating. For the first time, Japan participated with a fully combat-ready force, and Australia, Canada, France, and New Zealand also sent forces to collaborate in the drills. This exercise clearly focused on maritime strike and island defense, particularly the defense of the northern Philippine territories near Taiwan. China's military response to this has exhibited a rare multi-domain, multi-platform, and multi-layered comprehensive deterrence posture, which warrants in-depth analysis.

Aerial anti-ship strike capabilities became the most direct means of signal transmission from the Chinese side. During the exercise, the Southern Theater Command of the People's Liberation Army organized naval and air forces to conduct "combat readiness patrols" in the airspace over Scarborough Shoal. Two H-6 series bombers, armed with live ammunition, flew over the disputed waters under the escort of J-16 fighter jets. From publicly available footage, at least one J-16 was seen carrying a single YJ-91 anti-radiation/anti-ship missile, while the H-6 bombers were equipped with YJ-12 supersonic anti-ship missiles. The YJ-12 is currently China's most advanced medium-range air-launched supersonic anti-ship cruise missile, estimated to have a range of about 400 kilometers and a terminal penetration speed exceeding Mach 4, posing a serious threat to surface vessels. Notably, unlike previous H-6 patrols near Scarborough Shoal, the bombers deployed this time significantly increased the payload of anti-ship munitions, a configuration choice directly targeting the multinational fleet participating in maritime strike drills during "Shoulder-to-Shoulder 2026." Concurrently, the Southern Theater Command also dispatched two 054A-class frigates—Bayan Nur (551) and Tongliao (554)—as well as the 056A-class frigate Hanzhong (648), forming a joint sea-air monitoring network in coordination with the aerial formations.

The strategic deployment of the aircraft carrier strike group further elevated the level of deterrence. The Liaoning (16) aircraft carrier strike group traversed the Taiwan Strait into the South China Sea to conduct combat deployments around the time of the exercise, covering major shipping lanes in the South China Sea. Reports indicated that J-15 carrier-based fighter jet formations conducted large-scale formation flying training over the South China Sea. This marked the second time the Liaoning has conducted realistic deployments in the region following the Chinese Navy's first dual-carrier strike group exercise in the South China Sea in October 2024. The presence of the aircraft carrier not only provides a sustained platform for maritime air power projection but also strategically signals to participating countries in the exercise that any military presence in the South China Sea and surrounding areas falls within the strike radius of the PLA's naval and air forces.

Further out in the Philippine Sea, a surface combat group led by the 055-class destroyer Zunyi (107) conducted live-fire exercises in waters east of Luzon Island. The location of this task force is highly sensitive—it lies on a critical shipping route for the US-Philippine alliance to deliver reinforcements to the Philippines in a conflict scenario. In recent years, the US military has focused on eastern Luzon ports and bays as alternative logistical nodes to Subic Bay and Manila Bay, and the exercise area of the Zunyi task force precisely covers this strategic rear. The 055-class destroyer is equipped with a 112-cell universal vertical launch system, capable of carrying HHQ-9B long-range air defense missiles, YJ-18A anti-ship cruise missiles, and the YJ-20 hypersonic anti-ship ballistic missile, which is reportedly already in operational deployment. On April 25, 2026, reports indicated that a 055-class destroyer launched the YJ-20 hypersonic missile again in waters near the Philippines. Although independent verification is pending, the Southern Theater Command has publicly confirmed the existence of related exercises. The YJ-20 is estimated to have a range of about 1,500 kilometers and a terminal speed of up to Mach 10, capable of conducting long-range precision strikes against aircraft carrier strike groups. If this capability has indeed achieved initial operational capability, it would signify a critical leap in the PLA's anti-access and area denial (A2/AD) system in the Western Pacific from "denying entry" to "full coverage."

The electromagnetic dimension of the contest is also not to be overlooked. The Chinese Navy's 815A electronic reconnaissance ship AGI-797 Tianguanxing was confirmed on April 28 to be located within the exclusive economic zone of the Philippines at 14.8 degrees North latitude and 118.8 degrees East longitude, approximately 150 to 200 kilometers from Luzon Island. This ship belongs to the South China Sea Fleet, has a full displacement of about 6,000 tons, and is equipped with numerous antennas and radar arrays for passive interception of radar signals, communication data, and electronic signatures. Its deployment coincided with the "Shoulder-to-Shoulder 2026" multinational fleet conducting large-scale maritime exercises north of Luzon Island, providing China with a high-value window to collect real-time electromagnetic characteristics of the integrated command and control systems, tactical data links, and advanced radar platforms of the US-Philippine joint forces. Analysis from the SeaLight Foundation points out that this is the Chinese Navy's "standard operating procedure," systematically utilizing the inevitable electromagnetic exposure during multinational exercises to build a database of the opponent's electronic warfare sequences. The continuous accumulation of signals intelligence (SIGINT) will directly translate into tactical advantages in electronic warfare in future conflicts. At least four Chinese warships have been confirmed to have tracked a multinational maritime formation consisting of eleven vessels from the Philippines, the United States, Japan, Australia, and Canada, including the 815A reconnaissance ship, reflecting the Chinese Navy's systematic deployment capabilities in intelligence collection and maritime situational awareness.

In summary, the PLA's actions during "Shoulder-to-Shoulder 2026" demonstrate not isolated show-of-force patrols, but rather a meticulously designed multi-domain coordinated countermeasure system. From the bomber formations over Scarborough Shoal, the aircraft carrier strike group in the central South China Sea, the destroyer combat group east of Luzon Island, to the electronic reconnaissance ship in the western waters of the Philippines, these assets geographically create a three-sided encirclement of the Philippine archipelago, functionally integrating anti-ship strikes, regional air defense, electronic reconnaissance, and strategic deterrence. This deployment model indicates that the PLA's anti-access operational concept has evolved from a fixed denial based on the first island chain to a mobile, all-domain coverage centered around aircraft carrier strike groups and large destroyers.

From a broader perspective, the 2026 "Shoulder-to-Shoulder" exercise marks a significant acceleration in the construction of a military presence chain from northern Philippines to the vicinity of Taiwan by the United States and its allies. An opinion piece published by China's China Daily prior to the exercise explicitly pointed out that the Philippines allows "foreign forces to establish military footholds dangerously close to Taiwan and China's South China Sea islands." Against this backdrop, the PLA's multi-dimensional countermeasures are not only a display of tactical strength but also convey a clear strategic signal: any attempts to construct a military encirclement around China will face a comprehensive response from the increasingly mature PLA anti-access and area denial system. Future military interactions in the South China Sea will largely depend on how all parties perceive and adapt to this new deterrence pattern.