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* Rapid North Korean missile progress leaves Japan
* Upgrades to Japan BMD months away, new systems years out
* U.S. increasing number of Aegis-equipped destroyers in
By Nobuhiro Kubo and Tim Kelly
TOKYO, Oct 4 Successful rocket tests have
propelled North Korea ahead in a two-decade long arms race with
Japan, leaving Tokyo unsure it could fend off a missile strike
by the Pyongyang regime without U.S. help, military sources told
Under young leader Kim Jong Un, North Korea has test fired
21 ballistic missiles since the start of the year, an
unprecedented burst of activity that has rattled its neighbours
and the international community.
"Their progress has been faster than anticipated," a senior
Japanese military commander said. "There is a limit to what our
current ballistic missile defense system can achieve," he added,
asking not to be identified because he isn't authorized to speak
to the media.
Planned upgrades to Japan's ballistic missile defence (BMD)
are not due to begin until April at the earliest, while the
deployment of new systems designed to destroy incoming warheads
could take years to complete.
Constrained by production schedules and tight budgets that
limit its ability to accelerate those plans, Japan may instead
have to lean more heavily on its U.S. ally to guard against
attacks, the sources said.
"Our only option for now may be to rely on the U.S. to stop
them," said another source at Japan Self Defence Forces (SDF).
Tokyo and Pyongyang have been locked in an arms race since
1998 when North Korea fired a missile over Japan.
In June, a medium range Musudan rocket reached an altitude
of 1,000 km (620 miles) on a lofted trajectory, marking a
breakthrough that could allow Pyongyang lob warheads over the
range of Japanese BMD Aegis destroyers patrolling the Sea of
That would leave older PAC-3 Patriot missile batteries
protecting major cities including Tokyo as a last line of
defence. A $1 billion program to improve their range and
accuracy will begin after March, but the first will not be ready
until the 2020 Tokyo Olympics, sources previously told
Warheads from missiles such as Pyongyang's Rodong, with an
estimated range of 1,300 km (800 miles), travel at speeds of up
to 3 km (1.9 miles) a second. But rockets like the Musudan,
which can fly as far as 3,000 km (1,860 miles), plunge from
space at speeds reaching 21 km (13 miles) per second,
potentially too fast for existing Patriot batteries.
Japan's Ministry of Defense also plans to improve the
performance of SM-3 missiles on its small Aegis fleet. The SM-3
missiles are designed to hit warheads at the edge of space, but
the sources who spoke to Reuters were unsure they could tackle
A more powerful version of the SM-3 jointly developed by
Japan and the United States, dubbed the Block IIA, is nearing
completion, with Japan planning to buy the first of those next
year. It has not, however, said how many it will acquire, or
when they will be deployed.
Longer term, Japan is evaluating whether to buy Lockheed
Martin Corp's Terminal High Altitude Air Defence (THAAD)
system, to add a middle layer to BMD, or build Aegis batteries
on shore to bolster its defences.
Any roll out of those, however, would take several years
because of time needed to study the technology, secure funding
and build and integrate the systems, the sources said.
As Japan struggles to bolster its defenses, the U.S. is
stepping up help to neighbouring South Korea, promising last
week to speed up deployment THAAD batteries there.
"We still think they need time, but whatever the purpose is,
the North is doing things at a rate that is beyond our
imagination," South Korean Defence Minister Han Min-koo said in
parliament in late August.
Pentagon spokesman Commander Gary Ross said the United
States had recently reaffirmed its "unwavering and ironclad"
commitment to defend both South Korea and Japan, "guaranteed by
the full spectrum of U.S. military capabilities, including
conventional, nuclear, and missile defense capabilities".
"We continue to support (South Korean) and Japanese efforts
to strengthen their respective defense capabilities against the
North Korean nuclear and missile threat," Ross said in an
For now, Japan is making do with a diminished force. It has
four Aegis destroyers each equipped with eight SM-3 missiles.
Two of those, however, are laid up for maintenance leaving only
two available to watch for North Korean missiles, a third SDF
source told Reuters.
The heightened threat "comes just as we face a pinch with
our Aegis fleet," he said. "Cooperation with the U.S. Aegis
ships deployed in Japan is going to be crucial."
By March 2019 Japan plans eight BMD Aegis ships, but
training and maintenance means that only two ships will likely
be out on regular patrols at any one time.
U.S. reinforcements that could help cover more sky are,
however, sailing into the region. The U.S. Navy, as part of a
plan to bolster its presence formulated before North Korea's
latest missiles tests, has increased its BMD Aegis ships
patrolling the region to ten from seven in the past two years.
Whether that will prove sufficient to protect against
further North Korean advances is yet to be seen.
"North Korean ballistic missile technology is progressing
step by step and every time we raise our capability they improve
theirs," said a fourth SDF source.
(Additional reporting by Jack Kim in SEOUL and Idrees Ali in
WASHINGTON.; Editing by Lincoln Feast)