The Existential Estuary

NEW TAIPEI CITY, TAIWAN – Taiwanese forces mobilized mechanized units, engineering troops and mines across a river estuary crucial for the defense of the island’s capital city during the opening days of Han Kuang 42.

Among the paths for a potential Chinese invasion of the island’s capital, the approach from the Tamsui River will be critical for both attacker and defender.

Within a few dozen miles of the estuary is Taiwan’s largest airport, a deepwater port, several military facilities, a beach suitable for an invasion force with a straight shot via the river to downtown Taipei. For Chinese forces, the area’s landing points and logistics nodes are necessary for follow-on operations into the capital.

“The defense of Tamsui is important for Taiwan because it provides a direct route into Taipei. If the PLA wants to rapidly attempt entry into one of the most crucial parts of the city, where the presidential office is located, they could use the river as their primary means of approach,” Ben Lewis, founder of PLATracker, an organization dedicated to monitoring Chinese military activity and development, told USNI News following the drills.

“Ensuring that Taiwan’s forces have the capacity to deny free movement up the river is very important,” Lewis said.

In the event of a landing, the Taiwanese troops assigned to the defense of the Tamsui plan to delay Chinese forces through a series of kill zones, fortifications and obstacles. Over the past week at Han Kuang 42, components of these worst case scenario wartime plans were on full display throughout the city.

The 2026 iteration of the island-wide mobilization drills are throwing the troops of the Republic of China Armed Forces into uncertain situations.

From last-minute deployment orders to decentralized logistics and command, Han Kuang 42’s training activities contrast the heavily sequenced nature of iterations from past years and build upon improved training regimes from recent drills. Local reporters noted increased difficulty in the events available for coverage. In past exercises, outlets knew the dates of specific activities days in advance.

Bridge Blockers

Troops emplace repurposed wave breakers to block enemy vehicles from crossing the Danjiang Bridge on Aug. 6, 2026. USNI News photo A company’s worth of engineering troops and their vehicles were backlit by the warm glow of traffic lights on the north bank of the Tamsui River a few hours ahead of a training operation at Danjiang Bridge.

The 3,020-foot-long span was built to ease traffic congestion and lessen commute times. The bridge’s opening earlier this year also brought with it new considerations for Taiwanese defense planners due to the importance in linking the two banks of the Tamsui and critical infrastructure near Taipei. During a potential invasion, Chinese forces landing at Bali Beach or inserted via additional northern areas could use the bridge to rapidly deploy and seize nearby points of interest.

During Han Kuang, Republic of China Army engineering troops and local volunteers from the All-Out Defense Mobilization Agency worked to secure barricades on this new strategic route.

“The drill on Danjiang bridge, which sits at the mouth of the river, allowed Taiwan’s forces to practice denying PLA troops the capacity across the river, potentially using a northern approach to central Taipei,” Lewis said.

Held on late Thursday to lessen travel disruption, around a dozen military and civilian flatbeds made their way up from the north bank of the bridge to establish layers of barriers. Combined, the HESCO barriers, barbed wire and concrete wave breakers are envisioned to impede both enemy infantry and armoured vehicles.

In a wartime scenario, Taiwanese defenders could engage forces from both banks. Concentrated urban areas with multi-story buildings and high rises ring the southern and northern bank, which could be used by Taiwan Army infantry units to rain fire on an enemy force caught up in the blockade.

Taiwanese engineering troops prepare hedgehog tank traps and barbed wire on Aug. 6, 2026. USNI News photo Drones belonging to observers buzzed above the Taiwanese engineering troops, who got to work unfurling bushels of barbed wire and collapsible barricades. Cranes lowered a series of repurposed concrete wave breakers to complete the span of barriers.

While these drills were limited in the quantity of forces, men and material mobilized, the training carried out was “crucial to ensure that Taiwan’s engineering troops are prepared to secure these routes in wartime,” Lewis said.

Taiwanese troops told reporters during the drill that their aim was to set up barriers against a potential force approaching from the southern bank, an axis that involves a beach suitable for landing forces, northern Taiwan’s largest port and Taoyuan International Airport.

Mines and Tanks

A Republic of China Army M3 Amphibious Rig lays improvised explosive barrels Aug. 7, 2026, along the Tamsui River. USNI News photo A few miles upstream of the Danjiang Bridge, Taiwanese Marines and Army troops worked to get dozens of pontoons equipped with rigged explosive barrels across the width of the Tamsui.

The M3 Amphibious Rigs splashed into the water, laying four of the improvised explosives at a time. Originally procured by Taipei for conventional purposes, these amphibious bridging systems have shifted their mission to help Taiwanese defensive efforts along the Tamsui.

The rigs moved under the coverage of archaic Cold War-era tank guns. At least two platoons worth of CM series tanks, derived from the American M48 main battle tank, were shaded by camo netting while in concrete entrenchments.

An M3 Amphibious Rig prepares to get underway under the cover of two CM series tanks on Aug. 7. 2026. USNI News photo While outdated compared to China’s latest armored vehicles, their machine guns and 105mm guns could hold targets under threat attempting to use the river to get to downtown Taipei. Additional forces were spotted providing security during the mining drills, although their composition and equipment could not be identified.

Circling the mass of floating explosive barrels were small rubber boats with divers and additional personnel that helped emplace the pontoons to the riverbed. More than 50 of these makeshift mines were on the river and staged at the nearby defensive line.

Taiwanese forces regularly practice the deployment of these improvised mines throughout the year. As in recent Han Kuang iterations, these annual efforts are underlined by increased geopolitical tension that enhances the importance of these drills against potential Chinese operations in an invasion.

For Taiwan, an increased focus on countering decapitation forces in the opening hours and days of a cross strait conflict is paramount.

The drills around Tamsui were aimed at defeating a mobile force speeding toward key infrastructure and political targets upstream in Taipei, invoking experiences from the early hours of Russia’s 2022 invasion of Ukraine. The lessons that helped Kyiv take the first blow and continue the fight from four years ago may prove crucial for Taipei in a Chinese invasion.

Elsewhere in Taipei, President Lai Ching-te was escorted by a convoy of mechanized troops into one of the island’s secretive bunkers. Decoy movements helped mask his movement to the hardened command and control facility.

From these networks of bunkers and measures to defeat the initial movements of a decapitation strike, Taiwanese planners hope to weather the first few days to regroup and plan the defense of their island.