As two great powers in Northeast Asia, Japan and China have been rivals for centuries
Topping the list in Japan's deterrent against China is the Soryu-class diesel-electric submarine
This is one of the most advanced non-nuclear attack submarines in the world
With a displacement of 4,100 tons, the submarine can reach speeds of 13 knots on the surface and 20 knots submerged
The Soryu is equipped with six bow-mounted torpedo tubes, with a total of 20 Type 89 high-speed homing torpedoes and American-made Sub-Harpoon missiles
Japan’s submarines could also be the delivery vehicles for cruise missiles, should the concept of preemptive strikes
currently being debated in Japanese politics, become a reality
There are currently eight Soryu-class submarines, with more under construction
In response to increased tensions with China and a growing People’s Liberation Army Navy submarine fleet
in 2010 Japan decided to increase its own submarine force from 16 to 22
Japan's submarine fleet is especially worrisome for China, as the PLA Navy's weakest point is anti-submarine warfare
In fact, China has not practiced ASW in wartime and has been institutionally deficient in both skills and assets
Japan's next deterrent is the Air Self-Defense Force's F-15J air superiority fighter
The F-15J is a twin-engine heavy fighter
Japanese version of the F-15J, with slight differences from the original F-15 and domestically produced by Mitsubishi Heavy Industries
The F-15J is armed with the AAM-5 infrared homing missile, similar to the American Sidewinder missile, which it replaced
Complementing it will be the AAM-4B, a medium-ranged radar-guided missile and one of the few missiles in the world with an active-array radar seeker
Active-array radar missiles, of which China has none, dramatically increase both the range and the lock-on capability of radar-guided missiles
giving the F-15J a distinct advantage over Chinese adversaries
More than 200 F-15Js have been built
Despite being an old design, the F-15J is still a big challenge for the PLAAF
and after more than three decades of service, the F-15J is still arguably on par with any of China's most modern fighters today
Worldwide, the F-15 has a reputation as a particularly deadly fighter, with 104 aircraft kills and zero losses
In terms of warships, the Atago-class guided-missile destroyers are Japan's most capable surface warships, designed to take on a variety of missions
With a full load displacement of 10,000 tons, the Atago destroyers were comparable to Japan's World War II-era cruisers
The U.S.-designed Aegis radar system makes it a potent mobile air defense platform, capable of shooting down aircraft and ballistic missiles
Atago-class destroyers are equipped with 96 Mk.41 vertical launch missile silos, each capable of holding a single SM-2 surface to air missile
SM-3 ballistic missile interceptors, or ASROC anti-submarine rockets
Anti-ship armament consists of eight SSM-1B anti-ship missiles, roughly equivalent to the American Harpoon missile
while gun armament is in the form of one five inch gun and two Phalanx close-in weapons systems
Finally, each Atago can engage submarines with a SH-60 Seahawk helicopter and six deck-mounted Type 73 anti-submarine torpedoes
Currently, Japan does not have an aircraft carrier, but with the Izumo-class multi-purpose amphibious assault ship
it can be turned into an aircraft carrier for the F-35B aircraft
With a displacement of 27,000 tons and a length of 245 meters, the Izumo is the largest class of naval vessels built by Japan after World War II
With a full length flight deck and hangar, each Izumo can accommodate and service up to 14 helicopters
Armed with SH-60 anti-submarine helicopters, each Izumo could sweep a large area of water for submarines
Japanese helicopter destroyers are also used in amphibious roles for CH-47 Chinook transport helicopters and AH-64 Apache attack helicopters
Izumo could carry the number of a Japanese battalion, or a Western light infantry regiment, and transport them to shore via helicopter
China is also concerned about the Izumo class, as it is a multi-purpose aircraft carrier and an anti-submarine warfare (ASW) platform
as well as an amphibious vehicle
And as a special carrier, it can deploy several stealth fighters in the East China Sea
And finally, what scares China the most is the US military
The Treaty of Cooperation and Security between Japan and the US means that Japan has the strongest military in the world backing them
Of course, US participation in any Sino-Japanese conflict would be subject to strict conditions
Only if Japan is the victim of an armed attack and requires US military assistance
The US-Japan military alliance is one of America's great successes in the post-World War II era
Previously, the alliance was built against the Soviet Union, in an all-out war, not for Japan in a territorial dispute with China
The U.S. involvement in a Sino-Japanese conflict would almost certainly lead to an all-out war
However, as long as Japan and China's territorial disputes remain tense
it is possible that the US could be dragged into a local crisis and escalate into an all-out war