On October 20, 2025, Japan’s ruling Liberal Democratic Party (LDP) and Japan Restoration Party signed a coalition Agreement "Liberal Democratic Party-Japan Restoration Party Coalition Government Agreement".
This Agreement brings together the
long-dominant LDP and the reform-minded Japan Restoration Party under a shared
vision of national revival. It establishes policy cooperation across a wide
range of areas, including revising the constitution, defence build-up, fiscal
and social security reform, and governance restructuring, to build a
"strong and independent Japan" capable of responding to intensifying
domestic and international challenges.
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wispywood2344, a Japanese expert on submarines, missiles, other strategic issues and physics, who has reported reliably on Submarine Matters for many years. He commented in part at 10/26/2025 2:09 AM :
"Meanwhile, Japan recently saw a realignment of political parties and the formation of a new coalition government. The agreement between the ruling parties included the phrase “long-endurance submarines equipped with next-generation power plants and VLS and stand-off missiles”"
It is the 5th page of "Liberal Democratic Party-Japan Restoration Party Coalition Government Agreement" at https://o-ishin.jp/news/2025/images/624de5f22900f6e88e892abb49d3fc70ef3cac92.pdf#page=5
which includes in Japanese:
That translated into English states:
"In order to significantly strengthen Japan's deterrent power, we will accelerate the development of stand-off defense capabilities. From this perspective, we will steadily develop long-range missiles with counterattack capabilities and develop land-based deployments.
At the same time, we will promote a policy to possess VLS-equipped submarines equipped with long-range missiles and utilizing next-generation power sources that enable long-distance and long-term travel and submerged operation."
wispywood2344 comments that "this is widely seen as referring to SSGNs. In the distant future, “JUKUS-SSGNs” similar to “AUKUS-SSNs” may become a reality."
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Pete Comment
When the Agreement on page 5 mentions "Japan's deterrent power [and] counterattack capabilities and develop land-based deployments." I can interpret the drafters as meaning a long term strategic option of nuclear deterrence using ICBMs.
ICBM? Japan has been developing the dual-use Epsilon long range rocket/missile capability since 2007. (See image below) Epsilon is a 3 to 4 stage solid fuel rocket with no strap-on boosters. This Epsilons ideal for deployment in protective silos.
More see my article "Japan's Epsilon Rocket, An ICBM in Waiting" of December 22, 2013 at https://gentleseas.blogspot.com/2013/12/japans-new-military-buildup-seen-as.html
Japanese SSGN? Japan developed the nuclear powered ship Mutsu in 1972. This means Japan's prior development of a miniature marine reactor, more than 50 years ago, gives it the beginnings of a submarine reactor capability.
In the US context SSGNs (with Tomahawk missiles) are used for land attack. Land attack may be the main function envisaged for Japanese future SSGNs although anti-ship may be a secondary capability.
Japanese Hypersonic Missiles? Japan is developing a Hyper Velocity Gliding Projectile, (also see this and this video commentary here) with a booster it would be a hypersonic missile. A submarine launched variant is under consideration. Japan is also developing a Hypersonic Cruise Missile (HCM) (see page 22 of this US document). Japan's opponents in Northeast Asia would probably have great difficulty shooting them down.
Happy Sunday Pete,
ReplyDeleteA number of countries will have issues with a nuclear powered Japanese submarine, but South Korea has similar, and more public, ambitions, and most of the unaligned Southeast Asian nations won’t really protest much.
The China/Russia/North Korea axis will make the most noise, especially for internal posturing, but Japan and South Korea can easily counter that Xi has not reined in Kim, while Putin has actively encouraged him.
https://www.rusi.org/explore-our-research/publications/commentary/russia-now-actively-funding-north-koreas-nuclear-programme
As for ballistic missiles, Japan can say that they are simply keeping up with the neighbours.
https://www.channelnewsasia.com/east-asia/north-korea-ballistic-missile-south-military-5416616
I agree with Shawn. You can hardly call an armament decision escalatory when you are surrounded by hostile countries already doing the same thing. Japan is entitled to defend itself. If the international security promised by a formerly dominant USA is absent, multiple nations will look to gain their own deterrent.
ReplyDeleteHi Shawn at 10/26/2025 7:32 PM
ReplyDeleteIndeed a rearming Japan's many decades of invading and occupying neighbours, through to 1945, would cause neighbours to remember the past.
If Japan puts Epsilon ballistic or hypersonic missiles in silos (implying nuclear warheads) that would make its neighbours spit their dummies.
Cheers Pete
Hi Anonymous at 10/26/2025 7:49 PM
ReplyDeleteYes, if an isolationist US removed its protection of Japan, Japan would need to build its own nuclear deterrent forces.
Regards Pete
Pete we would too if we had each of China, North Korea and Russia all closer to us than New Zealand.
Delete