proposal

The Sino-Russian Strategic Partnership and Japan's Security: Future Trajectories and Implications1

Introduction

Russia's invasion of Ukraine in February 2022 became a landmark event, accelerating the transformation of the post-WWII international order. One of the central factors driving this shift is the deepening strategic partnership between China and Russia.

After the outbreak of war, both countries have maintained and strengthened their substantive partnership, sharing the strategic goal of countering the US-led order. However, if some form of "peace" were realized in Ukraine, how would their strategic partnership change?

To answer this question, this paper analyzes and discusses the outlook for the Sino-Russian relationship following the restoration of peace in Ukraine, as well as the potential impact of changes to this relationship on Japan's security environment.

1. The Deepening Sino-Russian Partnership

(1) Developments in the Sino-Russian Relationship

Since Russia's annexation of Crimea in 2014, the Sino-Russian relationship has continued to deepen. For Russia, which is subject to sanctions imposed by the United States and European countries, its relationship with China has become crucial. Meanwhile, as the US-China conflict intensified from 2018 to 2019, for China, too, the strategic importance of its relationship with Russia increased. In 2019, the two countries declared a "Comprehensive Strategic Cooperative Partnership for a New Era," and their bilateral relationship advanced to a quasi-alliance or just short of a military alliance.2 During President Putin's visit to China in February 2022, a joint declaration was issued, which expressed both partners' rivalry and hostility toward the United States, stating, "Friendship between the two states has no limits, there are no ‘forbidden' areas of co-operation."3

When Russia began its invasion of Ukraine, some speculated that this blatant act of aggression would constrain the Sino-Russian relationship and compel China to reconsider its relationship with Russia. Many Chinese seem to have felt that the expression "friendship with no limits" went too far.4 After that, this expression fell out of common use.

After the outbreak of war, China initially observed the situation for a short while but gradually manifested its pro-Russian stance. China did not call the Russian invasion an aggression, nor did it join in sanctions against Russia. China considers the United States to be the root cause of the Ukraine war and is reacting against what it perceives as US pressure on Russia and China through various means. China has since launched disinformation campaigns alleging that the United States was building biological weapons testing facilities in Ukraine.5

In March 2023, President Xi Jinping visited Russia for the first time after the outbreak of the war in Ukraine. The two countries declared "Deepening Comprehensive Strategic Cooperative Partnership for a New Era." In the context of China's partnership diplomacy, a declaration of deepening ties indicates that a particular relationship is progressing smoothly. This declaration confirmed that the Sino-Russian relationship had been maintained after Russia's invasion of Ukraine and proclaimed both countries' intention to further deepen it.

In 2025, the two state leaders paid mutual visits to commemorate the 80th anniversary of the victory in World War II. As a result, a joint statement was issued condemning attempts to "falsify the history of World War II" and "smear the image of liberators" and supporting the verdicts of the Nuremberg and Tokyo Trials as the "foundation for modern international law and order." The statement showed both leaders' position that China and Russia are protectors of the post-WWII order and that the United States and its allies are undermining it.

(2) Factors that Deepened the Sino-Russian Partnership

Then, what factors have contributed to deepening the Sino-Russian partnership?

1) Cooperation to Counter the United States

The foremost factor is the strategic interest of the two states in countering the United States and dismantling the US-led international order. Despite various differences and points of potential contention, China and Russia are deepening their relationship, for they have the common enemy in the United States.

At a meeting on March 21, 2023, during his visit to Russia, Xi Jinping showed his assessment of the situation, stating, "Changes (in international relations) unseen in a century are accelerating, and the structure of international power is undergoing major changes." China has been repeating this expression since around 2018; it suggests China's assessment of the international situation that major changes are taking place in the structure of the international system due to the decline of US hegemony and the multipolarization of power; that China and Russia are deepening their strategic cooperation to propel those major changes and counter US hegemony.

The two leaders' exchange on that occasion in front of TV cameras as they parted demonstrated their commitment to countering the United States and transforming international relations. Xi Jinping mentioned to Putin "great changes unseen in a century," stressing, "We will jointly promote these changes," to which Putin agreed.6

Xi's "changes in a century" discourse is perfectly aligned with President Putin's vision of a "post-West" world, one in which US hegemony will come to an end and a multipolar world order will emerge. China and Russia are forging not a mere temporary anti-US coalition; theirs is functioning as that of the revisionist powers seeking fundamental change to the current international system.

2) Support for Russia's War Efforts

Second, China finds benefits in supporting Russia's war sustainability. Since the outbreak of the Ukraine war, China has consistently been advocating a neutral stance of not directly providing weapons to Russia. This stance is believed to have a dual purpose. First, it aims to prevent Chinese companies from becoming the target of secondary sanctions imposed by the United States and European countries and to maintain connections to the global economy. Second, China aims to expand its influence over Global South countries by creating the image of a "peace mediator" distinct from both the West and Russia.

However, the reality of this "neutrality" is something extremely pro-Russian. China has continued to spread the Russian-made narrative that "NATO's eastward expansion is the cause of the Ukraine war" to the international community, particularly to the Global South, thereby effectively justifying the Russian aggression.

This attitude of China is not just passive support. China is having Russia continue the war in Ukraine, without risking crossing the red line of direct military intervention. The greatest benefit that China gains from this strategy is pinning down US and European military and economic resources exclusively in Ukraine. China's strategy of playing Russia and the West off against one another serves as a diversion, which exhausts the latter in Europe, diverts their attention, and, as a result, relatively reduces the US pressure that China faces in the Indo-Pacific.

Since the start of the Ukraine war, China has maintained a neutral stance regarding the conflict, or at least has avoided directly assisting Russia and has distanced itself from the conflict. China's relationship with Russia has been considered limited to the provision of dual-use goods. Arguably, China is trying to present itself to Global South countries as a neutral peacemaker, while also attempting to prevent Chinese companies from being targeted by economic sanctions from the United States and European countries.

In reality, however, China is gradually expanding its military-related trade and cooperation with Russia. This is a major reason why Ukraine, the United States, and the EU are taking a tougher stance toward China.

3) Sino-Russian Partnership Driven by the Leadership

Third, the current Sino-Russian partnership has deepened owing to the relationship between the two countries' political leaders, President Xi Jinping and President Putin. The two leaders have had talks 44 times to date; the recent deepening of Sino-Russian relations cannot be discussed without considering the trust between the two leaders. The joint statement issued during President Xi Jinping's visit to Russia in March 2023 stated that "guided by the consensus reached by the two heads of state," the bilateral relations would be ensured to progress.9

Chinese Foreign Minister Wang Yi stated, "The leadership of the two heads of state is the greatest political advantage and fundamental guarantee for the high-quality development of China-Russia relations."10

When discussing the Sino-Russian relationship, the relationship between the leaders is always emphasized as the driving force.

Xi Jinping regards Putin as an important partner. At their summit in March 2023, Xi Jinping mentioned the upcoming 2024 Russian presidential election and flattered Putin, "Under your strong leadership, Russia has made significant strides in its development and revitalization. I am confident that the Russian people will continue to give you their unwavering support."11 It is unusual for a Chinese leader to comment on the election of another country's leader. The fact that Xi Jinping nonetheless touched on this issue suggests that China believes Putin to be the Russian leader who best serves its strategic interests.

2. What Does Peace in Ukraine Mean?

What will happen to the Sino-Russian relationship if a ceasefire or some kind of political settlement (peace) is achieved in Ukraine? In conclusion, it is likely that the bilateral partnership will deepen rather than recede.

This is because the fundamental reason uniting China and Russia—the structural conflict with the United States—will not vanish due to peace in Ukraine. Rather, if the Ukraine crisis calms down (at least temporarily), US strategic concerns and resources will be refocused on the Indo-Pacific, where China is geographically located. If that happens, Russia's strategic value to China as a partner that could diffuse US pressure and secure its rear will increase rather than decrease. Based on this premise, post-peace Sino-Russian cooperation is expected to accelerate, particularly in two areas: military technology and the economy and finance.

(1) Military/Technical Cooperation: "Lessons" in Ukraine and Strategic Mutual Complementarity

Following the restoration of peace in Ukraine, Sino-Russian military cooperation is expected to enter a new phase. China will no longer be bound by its ostensible pledge of neutrality but will be able to propel Sino-Russian military cooperation. By the end of the war in Ukraine, the Russian military would have gained vast amounts of combat data on modern warfare—ranging from reconnaissance and attack operations using UAVs and the countering of electronic warfare (EW) exchanges, to the effective way to deal with HIMARS strikes, and even the vulnerabilities exposed by their own outdated weaponry. On the other hand, the People's Liberation Army of China, while remarkably modernizing its equipment, lacks large-scale combat experience. If the experiences that Russia acquired in Ukraine were systematically shared with the Chinese military, they would be of immeasurable value in improving the latter's combat capabilities. This would provide a major incentive for China to deepen military cooperation with Russia.

In this context, two areas of cooperation deserve particular attention.

First, UAV development and production.

It has become apparent that in the Ukrainian battlefields, cheap UAVs play a decisive role, while they are easily neutralized by electronic warfare. Meanwhile, Western countries are developing advanced operational techniques that combine fifth-generation fighter jets such as the F-35 with UAV swarms to penetrate the enemy's air defenses (A2/AD). Cooperation between China and Russia is likely to proceed in a manner that counters this Western advantage. Specifically, an approach combining the strengths of both countries will be adopted. Firstly, Russia's UAV operational data and anti-electronic warfare capabilities acquired during the war in Ukraine, and secondly, China's world-leading AI technology and substantial mass production capacity. This signifies a shift beyond mere joint weapons development, advancing toward the joint development and implementation of "asymmetric tactics" designed to neutralize Western air superiority. China and Russia have already deepened substantive cooperation in UAV production, which will serve as a foundation for deeper bilateral cooperation.

Second, cooperation related to strategic early warning systems.

Russia possesses sophisticated early warning satellite networks and ground-based radar systems for detecting and tracking ballistic missile attacks. Deepening bilateral cooperation in this area and jointly building early warning systems would bring about a significant change in China's nuclear strategy. Traditionally, China has abided by the principle of "no first use of nuclear weapons" (assuming a retaliatory attack). However, if it can develop a "launch on warning" posture with Russian technical assistance, its nuclear deterrent, particularly its second-strike capability (the ability to withstand the enemy's first strike and retaliate without fail), will be dramatically enhanced. This will directly link to creating a strategic environment that will enable China to deter US nuclear threats and to project conventional forces with ease in the event of a future Taiwan crisis.

(2) Economic Cooperation: Building a "Sanctions-Resistant" Infrastructure

Following the restoration of peace in Ukraine, China and Russia will accelerate the construction of an economic and payment infrastructure independent of US financial hegemony, going beyond mere sanctions evasion.

The sources of US power in the current international financial system are the US dollar's status as the reserve currency and its control over the international payment network through the Society for Worldwide Interbank Financial Telecommunication (SWIFT). The United States has weaponized these to exclude hostile nations such as Iran from the international financial system.

China and Russia perceive US financial hegemony as their crucial national security vulnerability. To counter this threat, China developed the Cross-Border Interbank Payment System (CIPS), while Russia developed the System for Transfer of Financial Messages (SPFS); they have agreed to link the two systems. CIPS, in particular, is not just a messaging system like SWIFT but can handle actual financial settlements.

In addition, both countries are accelerating the development of digital currencies (such as the digital yuan) that could serve as a trading infrastructure unrelated to SWIFT.

This series of Sino-Russian financial and economic cooperation can be seen as a move that assumes a Taiwan contingency in the future. Should China launch a military invasion of Taiwan, it will be almost certain that Western countries will impose financial sanctions on China, equal to or greater than those imposed on Russia (including the exclusion of Chinese banks from SWIFT). In that case, 1) securing energy and food supply lines by land from Russia will ensure China's physical logistics, and 2) CIPS/SPFS cooperation and digital currency will ensure China's financial logistics for settling relevant transactions.

3. Significance of Sino-Russian Strategic Partnership for Japan's Security

The deepening Sino-Russian strategic partnership will have a profound and direct impact on Japan's security environment, particularly on its defense planning with a Taiwan contingency in mind. The role that Russia would play in the event of a Chinese invasion of Taiwan will be a key variable for Japan's security.

Currently, since there is no permanent joint command between China and Russia, and their militaries' interoperability is not high, it is unlikely that Russian forces would participate in an invasion of Taiwan jointly with Chinese forces.

However, threats to Japan would come from a more likely scenario.

First, Russia's political and economic support for China. Russia would likely exercise its veto power in the UN Security Council to politically defend China's military actions. Russia would not join economic sanctions against China, but would continue to supply China with energy, food, and military supplies by land, thereby serving as a logistics line for China's "war economy." This move by Russia would significantly reduce the effect of a US-led sea blockade.

Second, Russia's strategic diversion. In this scenario, China launches military operations in the Taiwan Strait; concurrently, Russia activates demonstrations of forces in the Sea of ​​Japan, the Sea of ​​Okhotsk, or around Japan's Northern Territories, such as large-scale military exercises, missile launch drills, and access to Japanese airspace by using strategic bombers.

The resources of the Japan Self-Defense Forces and the US forces in Japan—particularly Aegis ships, fighter jets, and intelligence, surveillance, and reconnaissance (ISR) assets—are not limitless. Since a Taiwan contingency would have a direct impact on the defense of Japan's southwestern islands, the JSDF's response would prioritize the southwest region. However, if Russian forces simultaneously intensify their activities in the northern and western sectors, the JSDF would be forced to allocate valuable resources to monitoring and responding to such activities.

In short, the greatest military contribution Russia could make to China is to divert Japanese and US defense resources to two fronts: the southwest and the north and west. This would cause a serious dilemma for Japan's defense posture, exhaust Japanese and US response capabilities, and make it difficult to respond to a Taiwan contingency.

Conclusion

As analyzed in this paper, the Sino-Russian strategic partnership is not just a tactical "marriage of convenience," but is based on sharing a structural, long-term goal of transforming the US-led international order and an understanding of the situation pregnant with "great changes unseen in a century." Therefore, even if peace is achieved in Ukraine, it will be extremely difficult to disrupt the Sino-Russian relationship through short-term, tactical diplomatic efforts.

This reality strongly suggests two points for Japan's security policy.

First, Japan must formulate security policies on the assumption that the Sino-Russian strategic partnership will continue and deepen even after peace has been restored in Ukraine.

Second, Japan needs to develop a defense posture that considers a two-front situation in the event of a Taiwan contingency, in which Japan must simultaneously respond to Chinese forces in the southwest and Russian military diversions in the north and west, as the premise of standard defense planning, rather than a worst-case scenario.

To address this complex threat, it is imperative for Japan not only to further strengthen the deterrent and response capabilities of the Japan-US alliance but also to pursue a multi-layered framework for security cooperation, including strengthening cooperation among Japan, the United States, and South Korea.

(Shinji Yamaguchi, Senior Fellow, National Institute for Defense Studies)

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