Japan is ramping up its hypersonic weapons program amid mounting threats from China and North Korea, but technological gaps and dependence on the US defense industry could slow progress.
This month, Japan’s Ministry of Defense (MOD) announced that it has successfully conducted flight tests for its island defense hypersonic glide vehicle (HGV). Four test launches were conducted at a site in California, with one launch in August 2024, two in November 2024 and one in January 2025.
The stand-off missiles, designed to neutralize threats early and at long range, successfully demonstrated their expected flight performance, according to the Japanese language announcement. Japan’s HGV research will be completed by 2025 while mass production has been underway since 2023.
Previously, Japan’s Acquisition, Technology & Logistics Agency (ATLA) released footage of a successful test launch of the Hyper Velocity Gliding Projectile (HVGP) in July 2024, signaling apparent significant hypersonic weaponry progress.
The test showcased the “Early Deployment Version (Block 1)” with plans for extended-range variants by 2030.
The 900-kilometer-range HVGP will enter the Japan Ground Self-Defense Forces (JGSDF) service in 2026, and Mitsubishi Heavy Industries is reportedly speeding up the weapon’s production.
In March 2020, Japan unveiled two hypersonic weapon concepts: the Hypersonic Cruise Missile (HCM) and the HVGP. The HCM, powered by a scramjet engine, resembles conventional cruise missiles but offers higher speeds and longer ranges. Meanwhile, the HVGP features a solid-fuel rocket engine that propels its warhead and maintains high velocity while gliding to its target.
At the tactical level, hypersonic weapons are essential to Japan’s emerging counterstrike capabilities, although using them poses technical challenges.
HGVs and HCMs showcase advanced missile technology. Launched from ballistic missiles, HGVs can hit speeds of up to Mach 20 and glide unpredictably to evade interception. They can perform evasive maneuvers in the terminal phase if energy allows.
Conversely, HCMs utilize ramjets or scramjets for sustained speeds over Mach 6 and a booster for acceleration, enabling precise strikes in steep, fast dives.
In a February 2021 RAND report, Satoru Mori and Shinichi Kitaoaka explain the tactical rationale for Japan’s acquisition of hypersonic weapons. They mention that they can penetrate missile defenses and target critical infrastructure such as air and naval bases, logistics hubs and command centers.
However, Masashi Murano points out in a March 2024 article for the Hudson Institute that Japan lacks several critical components needed for deep strike operations, such as escort jammers and sufficient aerial tankers.
Murano notes that Japan has substantial gaps in intelligence, surveillance, reconnaissance and targeting (ISR-T) capabilities for hitting mobile, time-sensitive targets and still struggles to build warheads for hardened targets.
While Japan is speeding up its hypersonic weapons program to guard against a potential conflict in its disputed islands with China and Russia, and to deter regional missile threats, it must also address its critical dependency on the US and defense industry constraints.
As noted by Katsuhisa Furukawa in an April 2021 report for Open Nuclear Network, Japan could utilize hypersonic weapons to breach enemy defenses during a possible invasion of its remote islands, particularly in the Senkaku Islands contested with China.
Furukawa suggests launching them at multiple trajectories from multiple platforms to maximize the advantages of hypersonic weapons. He says that while those weapons could conceivably strike missile storage and launch facilities in China and North Korea, maneuvering could reduce their ranges, necessitating air-launch platforms like the F-35.
Furthermore, The Mainichi reported in December 2024 that Japan would earmark US$1.57 billion to speed up hypersonic weapons development.
That amount is on top of $130 million allocated to mass-produce long-range missiles starting this April in FY 2025. Japan will allocate $110 million to mass-produce an improved version of its Type 12 extended-range shore-based anti-ship missile and $19.75 million for a submarine-launched version.
However, Japan’s defense industry faces significant challenges in achieving these goals. Gordon Arthur mentions in an article for Asia Military Review this month that Japan remains dependent on imported US weapons and that its defense industry is uncompetitive because of small order sizes from the Japan Self-Defense Forces (JSDF) and self-imposed export restrictions.
He mentions that Japan has implemented a direct financial support scheme for its defense manufacturers to address those shortfalls.
However, Grant Newsham says Japan’s long-term overreliance on the US has hobbled its ability to defend itself. He assesses that Japan cannot defend itself alone against China, let alone adding in North Korea and Russia, and that there is no substitute for the US defense “services” in Asia.
As for the strategic impact of Japan’s counterstrike capabilities, Fabian Hoffman mentions in a May 2024 article for the peer-reviewed Journal of Strategic Studies that long-range conventional strike (LRS) weapons, such as cruise, ballistic and hypersonic missiles, have four primary strategic functions: counter-population, strategic interdiction, counter-leadership and counterforce.
He mentions that LRS weapons can weaken an adversary’s will or capacity to resist by targeting enemy populations, critical infrastructure, leadership and military assets.
Japan’s National Security Strategy 2022 and National Defense Strategy 2022 outline the country’s rationale for acquiring conventional counterstrike capabilities in a complex security environment.
The National Security Strategy emphasizes the need for proactive measures to safeguard Japan’s sovereignty and regional stability, citing escalating missile threats and geopolitical competition.
Meanwhile, the National Defense Strategy highlights counterstrike capabilities as essential for deterring and disrupting missile attacks. It stresses that these capabilities will be used as a last resort under constitutional and self-defense principles to bolster deterrence while maintaining Japan’s defense-oriented policy.
At the same time, Japan’s efforts to build counterstrike capabilities may stoke a regional arms race.
Michiru Nishida mentions in a November 2023 article in the peer-reviewed Journal for Peace and Nuclear Disarmament that China has expressed significant concerns about Japan’s development of intermediate-range missiles, particularly regarding their dual-use nature, which means they could carry conventional or nuclear warheads, with some voices pushing for Japan to procure the latter.
From China’s perspective, Nishida says ensuring these missiles are not equipped with nuclear warheads is vital to avoid a regional arms race and reduce the risk of miscalculation. However, he says China remains skeptical of Japan’s military intentions, perceiving these missile developments as a potential threat to its security and regional influence.
