Japan Long Term Planning ICBM as well as SSGN Capabilities? Hypersonic Missiles

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:

lわが国の抑止力の大幅な強化を行うため0スタンド・オフ防衛能力の整備を加速化

する観点から0反撃能力を持つ長射程ミサイル等の整備及び陸上展開先の着実な進

展を行うと同時に0長射程のミサイルを搭載し長距離・長期間の移動や潜航を可能

とする次世代の動力を活用したVLS 搭載潜水艦の保有に係る政策を推進するu 

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.