China builds, Cambodia benefits, and Beijing's influence grows.
In the shadow of China's deepening economic embrace of Southeast Asia, Japan's defence minister traveled to Cambodia and Vietnam this week to offer something harder to quantify than a canal: a strategic partnership rooted in shared concern over maritime security and regional autonomy. Tokyo's outreach reflects a long-standing truth of great power competition — that influence is built not only through infrastructure and investment, but through the patient cultivation of trust and military cooperation. The visit arrived on the very day Cambodia broke ground on a $1.7 billion China-backed canal, a coincidence that captured, in miniature, the broader contest now unfolding across the Indo-Pacific.
- China's infrastructure investments — from Cambodia's new canal to the expanded Ream naval port — are quietly converting economic dependency into political loyalty, reshaping the regional balance before most of the world has noticed.
- Japan, watching Beijing consolidate influence across critical shipping lanes, is racing to build defence partnerships it largely neglected for decades, now elevating ties with Cambodia and Vietnam to 'comprehensive and strategic partnership' status.
- The $1.7 billion Funan Techo canal, stretching 180 kilometres to the Gulf of Thailand, is framed by Phnom Penh as economic liberation — but to regional observers, it reads as another thread in China's web of leverage over a strategically vital nation.
- Cambodia's role as Beijing's quiet ally inside ASEAN gives China a diplomatic buffer against collective criticism over South China Sea disputes, making Tokyo's courtship of Phnom Penh as much about multilateral politics as bilateral ties.
- Japan brings history, values, and military cooperation to the table; China brings billions in investment and geographic proximity — and the region is watching to see which currency buys more lasting loyalty.
Japan's defence minister Minoru Kihara arrived in Cambodia this week with a clear but difficult mission: to deepen military ties with a country that has drifted steadily into China's orbit. He met with Cambodia's top leadership — defence minister, prime minister, and the influential former prime minister Hun Sen — to discuss disaster relief cooperation, military training, and the exchange of military attachés. The two countries agreed to establish a joint rescue training course, building on a long-dormant 2013 memorandum of understanding. From Cambodia, Kihara continued to Vietnam, where Japan has similarly elevated the relationship to the level of 'comprehensive and strategic partnership.'
Tokyo's interest in these countries is strategic, not sentimental. Cambodia and Vietnam sit astride some of the world's most critical shipping lanes, and Japan is acutely aware that China has been using aid, investment, and infrastructure to lock in political loyalty across Southeast Asia. The stakes were made vivid by the timing of Kihara's visit: on the very day he was meeting Cambodian officials, the country broke ground on the Funan Techo canal — a $1.7 billion project financed by China, stretching 180 kilometres from Phnom Penh to the Gulf of Thailand. Cambodia frames the canal as economic necessity, reducing shipping costs and ending dependence on Vietnamese ports. But it is also the latest in a series of Chinese infrastructure investments that have steadily deepened Beijing's leverage over Phnom Penh, following the controversial expansion of the Ream naval base in 2022.
What makes Cambodia particularly significant is its role within ASEAN. As a reliable diplomatic partner for Beijing, Cambodia helps China soften the bloc's collective response to its assertiveness in the South China Sea — making Japan's courtship of Phnom Penh as much about regional multilateral politics as bilateral defence ties. Kihara's message to both countries was that Japan understands the strategic environment and wants to help them navigate it. What went unspoken, but hung over the entire visit, was the harder question: whether Japan's offer of partnership and shared values can compete with the concrete weight of Chinese money and proximity. The answer will help determine the shape of the Indo-Pacific for a generation.
Japan's defence minister arrived in Cambodia on Monday with a straightforward mission: to deepen military ties with a nation that has drifted steadily into China's orbit. Minoru Kihara sat down with Cambodia's defence minister Tea Seiha, Prime Minister Hun Manet, and former prime minister Hun Sen—now president of the Senate—to discuss cooperation on disaster relief, military training, and personnel exchanges. The talks were cordial and concrete: the two countries agreed to establish a joint training course for rescue operations and to station military attachés in each other's capitals, building on a 2013 memorandum of understanding that had largely gathered dust.
Japan's interest in Cambodia and Vietnam is not sentimental. These are countries that sit astride some of the world's most critical shipping lanes, and Tokyo is acutely aware that China has been using aid, investment, and infrastructure projects to lock in political loyalty across Southeast Asia. Japan has few levers of its own in Cambodia—its influence is minor compared to Beijing's—but it is trying to build them. Before departing for the region, Kihara told reporters that Japan had elevated its relationships with both Cambodia and Vietnam to the level of "comprehensive and strategic partnership," a diplomatic formulation meant to signal serious, long-term commitment.
The timing of Kihara's visit underscored the stakes. On the same day he was meeting with Cambodian officials, the country broke ground on the Funan Techo canal, a $1.7 billion project financed and championed by China. The canal will stretch 180 kilometres from Phnom Penh to the coastal province of Kep, carving a path to the Gulf of Thailand. When completed, it will be 100 metres wide and 5.4 metres deep—large enough to handle significant commercial traffic. Cambodia's government frames the project as an economic necessity: the canal will reduce shipping costs and cut the country's dependence on Vietnamese ports, giving it direct access to the sea without having to route goods through a neighbour with whom relations are perpetually strained.
But the canal is also a symbol of something larger. China has woven itself into Cambodia's economy and politics through a series of major infrastructure investments, each one deepening Beijing's leverage over Phnom Penh. In 2022, China helped Cambodia break ground on an expansion of a naval port at Ream, a project that alarmed the United States and others who worried it could become a Chinese military base on the Gulf of Thailand. Cambodian officials have consistently denied this, insisting their country maintains a neutral defence posture and that China will have no special privileges. Yet the pattern is unmistakable: China builds, Cambodia benefits, and Beijing's influence grows.
This is the regional dynamic that worries Tokyo. Cambodia is not just any country—it is a key diplomatic partner for Beijing within the Association of Southeast Asian Nations, a ten-member bloc where several countries are locked in territorial disputes with China over the South China Sea. Cambodia's alignment with China helps Beijing manage criticism from within ASEAN, softening the bloc's collective response to Chinese assertiveness. Japan, by contrast, is trying to offer an alternative: defence cooperation, military training, and a partnership based on shared concern about China's aggressive maritime behaviour and its growing economic dominance.
Kihara's message to both Cambodia and Vietnam was that Japan understands the strategic environment in Southeast Asia and wants to help them navigate it. He spoke of Japan's commitment to the region, of the importance of these sea lanes to Tokyo's own security and prosperity. What he did not say, but what hung over the visit, was the question of whether Japan's overtures could compete with the concrete benefits China was offering—the billions in investment, the infrastructure projects, the economic ties that bind Cambodia ever more tightly to Beijing. Japan has history and values on its side. China has money and proximity. The outcome of that competition will shape the region for years to come.
Citações Notáveis
Southeast Asian countries are in strategically important areas that are part of Japan's crucial sea lanes.— Defence Minister Minoru Kihara
A Conversa do Hearth Outra perspectiva sobre a história
Why does Japan care so much about Cambodia, a country where its influence is admittedly minor?
Because Cambodia sits on a crucial sea lane, and because China is using infrastructure investment to lock in political loyalty across the region. If Japan loses Cambodia entirely, it loses a voice in ASEAN and a foothold in Southeast Asia.
But Cambodia just broke ground on a Chinese-backed canal on the same day Kihara was visiting. Doesn't that suggest Japan is already losing?
It does suggest that. But Japan is playing a longer game—trying to offer an alternative partnership, showing that it can be a reliable security partner even if it can't match China's investment dollars.
What does Japan actually get out of deeper military ties with Cambodia and Vietnam?
Access to the region, influence over how these countries respond to Chinese assertiveness, and the ability to shape the security environment around critical shipping lanes that matter to Japan's own economy.
Is Cambodia really neutral on China, or is that just what officials say?
The actions speak louder than the words. A $1.7 billion canal, a naval port expansion, consistent alignment with Beijing in regional forums—that's not neutrality. That's alignment.
What's Vietnam's position in all this? Why is Japan visiting there too?
Vietnam has its own disputes with China over maritime territory, so there's natural alignment there. But Vietnam is also wary of being seen as too close to any single power. Japan is offering Vietnam a way to balance Beijing's influence without appearing to choose sides.
Does this competition between Japan and China over Southeast Asia ever turn into actual conflict?
Not yet. But the more China tightens its grip through infrastructure and military projects, the more Japan and other countries feel they need to push back. That tension is the real story.