Recent tension between the China and Japan in the East China Sea has raised the possibility of armed conflict the two countries. The two historical antagonists have not fought since 1945, in part because China has been unable to project power beyond its borders.

Two decades of double digit defense budget increases for the People’s Liberation Army have sharply changed that. China now has more ships and planes than Japan, and appears to have a large, modern force in mind to challenge U.S. forces in the Western Pacific.

Although unlikely, the possibility of the second and third largest economies in the world slugging it out is a fearsome prospect. Even more so is the likelihood that the United States would be drawn into the conflict.

The decision to go to war

There are several reasons why China and Japan might go to war. A minor incident over the East China Sea might spiral out of control. China might decide to settle old scores, such as avenging its loss in the 1894-1895 Sino-Japanese War and losses during World War II. The Communist Party, facing domestic tensions, might start a war to rally the country.

In any event, in our scenario China has decided it is time to settle the Japan issue. The Party orders the People’s Liberation Army to inflict a humiliating blow on Japan that will drive it into a position of neutrality. Furthermore, a victory would drive a wedge between the United States and Japan, ending the alliance and driving American forces back to Guam.

Plan of attack

Ironically, China has not seriously prepared for war with Japan. However China has built up the capability to conduct an air and naval blockade of Taiwan, seeking to “degrade Taiwan’s defenses, neutralize Taiwan’s leadership, or break the public’s will to fight.” As the PLA’s abilities increase, these plans can scale towards larger, more distant country—like Japan.

The PLA analyzes Japan’s strengths and weaknesses—as well as its own—and draws up plans for a lightning campaign. First, the PLA will launch a surprise attack with a barrage of ballistic and cruise missiles. The objective of these strikes will be to degrade Japan’s ability to defend itself, leaving the country at the mercy of China.

The main force for this attack on Japan would be the conventionally-armed ballistic missiles of China’s Second Artillery Corps. The Second Artillery oversees all long-range missiles, both ballistic and cruise, armed with both conventional and nuclear warheads.

Next, the main islands of Japan will fall under blockade. The PLAN will fight its way east beyond Japan, destroying surviving Japanese air and naval forces. Japan will be cut off from the rest of the world. American naval forces will then be kept at bay with anti-ship ballistic missiles.

Among the major powers, Japan is particularly vulnerable to blockade. An island country with few resources and scarce arable land, modern Japan’s existence depends on secure air and sea lanes. Japan imports 60 percent of its food and 85 five percent of its energy from abroad.

Its ties to the outside world severed, Japan would have no choice but to surrender.

The Americans

Under the terms of the U.S-Japan Treaty of Mutual Cooperation and Security, Washington is bound to help defend Japan. Japan is a popular ally in the United States, and public sentiment could push the United States to help defend it, regardless of circumstance.

China has few good options for dealing with America. China has enough firepower for a surprise attack and short war on its terms, but if it carries it out, China would make the same mistake Japan made at Pearl Harbor. Even if China were to cause heavy losses among U.S. forces in Asia, the Americans would continue to flow ships, planes and ground forces into the area as reinforcements.

Under our scenario, the PLA believes a powerful enough blow against American forces in the region will force the U.S. to cut its losses, throw Japan under the bus, and sue for peace.

Sounds naïve? It’s happened before.

Phase One

The first stage of a Chinese attack on Japan would consist of cyber attacksagainst the whole of Japanese society. Cyber has the unique ability to disrupt civilian life while causing few if any casualties. China would be targeting public opinion—the center of gravity in a democratic society—by demoralizing Japanese civilians.

China’s army of hackers go after banks, stock exchanges, communications, energy grids, transportation networks and logistics systems, with the goal of disrupting normal life as much as possible. Cyber attacks would go on for days or even weeks ahead of kinetic attacks, in some ways duplicating the intent of aerial campaigns from previous wars—without much of the lethal effects against civilians.

Also during this phase, specialized PLAN submarines begin cutting undersea fiber optic cables servicing Japan. Japan’s Internet—already hammered by hackers—begins to intermittently lose contact with the outside world. Undersea cables are difficult to inspect, and so the sabotage is not discovered until after the war.

One interesting aspect of the cyber phase is that cyber operations are a gray area that occur both in peace and war. Thus, it would not necessarily follow to Japanese officials that the cyber operations are the opening phase of an actual war. This could allow the PLA to continue a military buildup without triggering the scrutiny of Japanese intelligence.

At the same time, strong electronic warfare jamming attempts to mask the mass movement of Chinese ships, aircraft and ground-based missile launchers. Chinese submarines depart naval bases with the objective of shutting down shipping in and out of Japanese ports, and Chinese surface task forces sortie to take on the Japanese Maritime Self Defense Force. Giant wheeled launcher vehicles of the Second Artillery Corps, loaded with cruise and ballistic missiles, lumber towards the coast opposite Japan.

Phase Two

The blockade of Japan begins not at sea, but in space: Chinese anti-satellite weapons, masquerading as satellite launches, target Japanese communications and navigation satellites.

Roughly an hour later the main attack commences, consisting of a swarm of DF-10 and DF-20 land attack cruise missiles, launched from ground-based mobile launchers and H-6K bombers circling over China. With a range of 2,500 kilometers, accuracy of up to ten meters and a 500 kilogram warhead, these cruise missiles would be ideal first-strike weapons for China.

U.S. and Japanese air defense forces are overwhelmed, confronted by nearly two hundred incoming missiles whose launches are timed to overwhelm defending Chu-SAM and Patriot PAC-2 missile defenses. Many Chinese cruise missiles are shot down, but many find their targets. Surface to air missile batteries would be targeted, both units in barracks and in the field. The AN/TPY-2 ballistic missile radars at Kyogamisaki Submarine Base, outside of Kyoto and Shariki Base, nearAomori, are struck to blind Japan to the second wave of the attack.

Japan Maritime Self Defense Force naval bases at Maizuru, Sasebo, Yokosuka and major locations are also hit by cruise missiles, with individual MSDF ships targeted port-side. These bases are easily monitored by Chinese intelligence, which could quickly feed updated target data back to Beijing via the Internet or satellite communications.

The attacks continue with missile strikes against Air Self Defense Force bases. Runways are targeted by DF-10s carrying submunitions, the intent being to temporarily shut down runways at Naha, Miho, Nyutabaru, Gifu, Komatsu and Komaki Air Bases.

The BMD radars at Kyogamisaki and Shariki destroyed, China launches the second, even more devastating wave. DF-16 and DF-21 ballistic missiles are launched against static targets across Japan. Military headquarters, command and control facilities, energy facilities and air force bases are pummeled by ballistic missiles launched from the mainland. Strikes against air bases are more comprehensive; while the first wave of cruise missiles merely pinned Japanese and American aircraft in place, the second wave of ballistic missiles go after hangars, control towers, fuel bunkers and ammo bunkers.

American targets are also hit. The headquarters of both Japan’s Air Defense Command and U.S. Forces Japan, Yokota Air Base is a key target. U.S. forces are also struck at Yokosuka, home of the 7th Fleet. Kadena Air Base on Okinawa, a major hub of American air power in Asia, is pummeled by conventional warheads streaking down from near space.

One of the most important targets is the USS Ronald Reagan, the 7th Fleet’s forward-deployed aircraft carrier. If the Reagan isn’t taken out of action, she will hunt down Chinese surface task forces and the naval blockade will be defeated. Ideally, the attack would begin while the Reagan was in port, allowing China to conserve its DF-21D “carrier killer” missiles and hit the Reagan with ordinary precision-guided ballistic missiles.

Only a handful of Chinese ground forces are used in the attack; China’s four Type 071 amphibious landing ships land troops on Miyakojima and Ishigakijima, two inhabited islands in the Ryukyus, in order to neutralize their anti-ship missiles and secure the Miyako Strait. Both islands fall quickly to Chinese marines, although several Chinese ships are damaged by Type 88 anti-ship missiles. China’s two Zubr-class assault hovercraft land troops on the Senkaku/Diaoyu islands, but depart after filming the planting of the national flag.

In our scenario China avoids hitting Guam, under the rationale that striking American territory would be an unnecessary escalation. Not attacking Guam, our Chinese planners reason, might allow the United States to sue for peace while saving face.

Phase Two

Now that Japanese and American air and naval forces have been dealt a serious blow, the blockade begins. PLAN surface task forces set out to form a barrier between Japan and the rest of the world. Lacking significant, effective long-range reconnaissance forces, Chinese forces at sea patrol aggressively but are at a disadvantage.

China continues its blitz of cruise and ballistic missiles, shifting their focus. Energy, food and transportation assets are struck, designed to quickly whittle down the quality of life of the average Japanese civilian. The race is on to break the Japanese government’s will to resist before China runs out of missiles and American reinforcements arrive. China strenuously denies it is hitting non-military targets.

Now comes China’s ace-in-the-hole: the DF-21D. China has avoided using its so-called carrier killer missiles, for fear of exposing the network of ocean-monitoring sensors making up the DF-21’s “kill chain.” China has even resisted using them on Japanese helicopter carriers hunting down Chinese submarines. China warns America that any aircraft carriers nearing Japan would be destroyed, as will the 5,000 Americans on board.

Meanwhile, Japanese and American forces in the region are licking their wounds, reorganizing defenses and absorbing reinforcements. Japanese and American forces that have escaped damage, particularly submarines at sea, will soon be on the offensive.

Conclusion

The above scenario represents the best possible outcome of a Chinese attack on Japan, given the current status of forces on both sides.

There are many unknowns riddling this exercise, and it assumes—for the sake of argument —that Chinese capabilities are good enough to inspire confidence. Without these assumptions, the Chinese war plan falls apart.

We know very little about Chinese cyber capability, for example, other than they have a prodigious number of hackers. Some experts argue China’s cyber capability is relatively primitive compared to Western capabilities. Chinese ASAT capability is also an unknown, and the sensors making up the DF-21D kill chain largely theoretical.

This thought exercise is not an endorsement of war between China and Japan, or even a suggestion war is likely. Rather, it is a reminder the possibility exists of a war that would affect nearly two billion people. The time to avoid it is now.

Kyle Mizokami is a writer based in San Francisco who has appeared in The Diplomat, Foreign Policy, War is Boring and The Daily Beast. In 2009 he cofounded the defense and security blog Japan Security Watch.