The Self-Defense Forces have come far. Their next decade will be defined by ongoing minesweeping and the rising burden of scrambles against Chinese threats.
SDF Series 1-001

A live naval mine removal drill by the Maritime Self-Defense Forces' minesweeping unit off the coast of Iwo Jima, a significant World War II battleground. June 21, 2024 (©Sankei by Toyohiro Ichioka)

July 1 marked the 70th anniversary of the founding of Japan's Self-Defense Forces (SDF). In this series, we explore the current status and challenges faced by the SDF in an increasingly complex security environment.

First in a 5-part series

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Mine Removal: A 'Psychological Battle'

Boom... A shockwave surged from beneath the wooden deck of the minesweeper. Simultaneously, the sea surface about 800 meters away swelled. With a roar, a sand-laden black-and-white water column shot up about 30 meters. "Water column sighted, explosion successful," the ship's broadcast announced. The explosion on the seabed was caused by a naval mine equipped with a magnetic sensor that detonates in response to the proximity and noise of ships.

Mine removal is the primary mission of the Maritime Self-Defense Force (JMSDF) minesweeping unit. On June 21,  it conducted a live mine disposal drill off the coast of Iwo Jima in the Ogasawara Islands

This year marks the 70th anniversary of the establishment of the Ground, Maritime, and Air Self-Defense Forces. Although they have never engaged in actual combat, the minesweeping unit alone has experienced "combat deaths" caused by enemy mines. Such a tragic event occurred in 1950 when they were a subordinate organization of the Japan Coast Guard. At that time they were tasked with a mission at the request of United Nations forces during the Korean War.

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Fast Forward to 2024

During the acoustic and magnetic minesweeping training on June 21, the minesweeper navigated slowly at about 10km per hour. It towed an acoustic device that emitted the sound of a passing ship and a cable that generated a magnetic field using an electric current to detonate the mines on the seabed.

"We assess the enemy's intentions. If we assume the mines are targeting an aircraft carrier, we produce sounds and magnetic fields similar to those of an aircraft carrier," explained a member of the JMSDF. Mines can also be set to detonate after a certain number of passes, so they do not necessarily activate on the first pass. However, the minesweeper must pass through the area multiple times.

"It is truly a psychological battle," he said.

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Seeking Optimal Balance with Advanced Technology

Mine warfare, a cost-effective method for maritime blockades, has long been a traditional strategy in naval operations. During World War II, the United States military laid about 12,000 mines. Meanwhile, the Imperial Japanese Navy (IJN) deployed approximately 55,000 mines. After the war, the explosions of these remaining mines caused casualties among civilian merchant ships. As a result, the former naval minesweeping units were reorganized into the Japan Coast Guard to continue their mission of mine removal and ensuring safe passage in Japanese waters.

Naoyuki Agawa is an emeritus professor at Keio University and an expert on US-Japan history. He highlights the importance of these efforts in his book Friendship Across the Seas (Springer, 2023). Those Japanese minesweepers, he writes, "laid the essential foundation of the postwar relationship between the Japanese and US navies, the thread connecting the IJN to the JMSDF." Minesweeping missions, along with anti-submarine warfare, remain key areas where the US military relies heavily on the JMSDF.

However, now there is a rising cost of constructing escort vessels and increasing personnel shortages. Therefore, the JMSDF is transitioning from specialized minesweeping units to more advanced solutions. They are now focusing on new escort vessels (FFM) equipped with unmanned minesweeping systems.

Toshihide Noma, the 50-year-old Captain of the Mine Sweeper Division One, shared his perspective on this shift: "We are seeking the optimal balance between human effort and machine reliance." He confidently added, "Our meticulousness, unique to the Japanese, makes us the best in the world at mine removal. Manned minesweeping units still have their value."

UAV Response Still Unaddressed

The F-15J fighter jet vanished into the azure sky in an instant, accompanied by a deafening roar. At 15-second intervals, a total of four aircraft took off. The Naha Air Base of the Japan Air Self-Defense Force (JASDF), located about 400 kilometers from the Senkaku Islands (Ishigaki City, Okinawa Prefecture), is crucial for the defense of the Southwest Islands. Pilots on standby 24/7 are required to take off within minutes of receiving a scramble order to guard against airspace violations.

An F-15J fighter jet (right) and ground crew members at the JASDF Naha Air Base. The jets take off within minutes of receiving a scramble order. (©Sankei by Naoki Otake)

"Chinese aircraft frequently enter the Pacific side," remarked Tomoyuki Yamamoto. He is a 41-year-old lieutenant colonel with the JASDF's 204th Tactical Fighter Squadron. In 2023, the JASDF conducted 669 scrambles to intercept unidentified aircraft entering the Air Defense Identification Zone (ADIZ) and confirm their nationality and intentions. Over 70% of these incidents involved Chinese aircraft.

In May 2023, Chinese unmanned aerial vehicles (UAVs) traveled between Japan's westernmost Yonaguni Island and Taiwan. They moved south from the East China Sea into the Pacific. These UAVs were not only for reconnaissance but were also capable of conducting attacks and flying at high altitudes.

There's a strong belief that this is part of a cost-imposition strategy, using low-cost UAVs to exhaust opponents. Masayoshi Okuda, a 48-year-old lieutenant colonel and Southwestern Air Defense Force Plans and Operations Commander, explained. "UAVs can reportedly fly for over 10 hours. Fighter jets, however, cannot sustain long flights. As a result, repeated scrambles are necessary, which imposes a significant burden on operations."

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Guiding the Self-Defense Forces 

The JASDF was established on July 1, 1954. It began its mission to counter airspace violations in February 1958, taking over from the US forces stationed in Japan.

In 1976, amid the easing tensions of the US-Soviet Cold War, Japan formulated its first National Defense Program Guidelines, or "Showa 51 Guideline" in Japanese. This initiative aimed for the JASDF to constantly monitor and patrol almost all airspace around Japan. To achieve this, 13 fighter squadrons and fixed radar sites at 28 locations nationwide were deployed. This system has been maintained for nearly half a century.

The Showa 51 Guideline viewed the existence of the Self-Defense Forces as a deterrent. In doing so, it introduced the concept of a "Basic Defense Force." This concept aimed to maintain sufficient defense capabilities to avoid a "power vacuum" in the region. 

Nearly 50 years later, the world has entered an era of great power competition, primarily between the US and China. As a result, Japan now faces its most challenging security environment since World War II.

Indo-Pacific at the 'Primary Front'

The focus of global conflict has shifted from Europe during the Cold War to the Indo-Pacific region. General Yoshihide Yoshida, the highest-ranking officer of the SDF, recognized this. He explained, saying, "We are standing at the frontline of the primary front."

The JASDF frequently scrambles manned aircraft in response to Chinese UAVs. It is an asymmetric and resource-intensive task that is increasingly burdening the force. In response, the SDF is exploring a transition away from the traditional Basic Defense Force concept. They are seeking to evolve from merely an "existing" force to a fully "functional" Self-Defense Force.

Despite some calls within the JASDF to reassess the heavy reliance on scrambles, the deployment of JASDF units still fundamentally prioritizes scramble missions.

JASDF officials nevertheless acknowledge that Russia's invasion of Ukraine has prompted a reevaluation of traditional strategies that focus on maintaining air superiority with fighter jets. The 2022 National Defense Strategy emphasizes enhancing unmanned equipment as a key pillar of defense capabilities. However, a senior official from the Ministry of Defense admits, "This goal has yet to be fully addressed."

For 70 years, the SDF has not engaged in combat. However, there is no guarantee they will remain out of conflict in the future. Their lack of combat experience remains a critical vulnerability.

Next in Part 2: 70 Years of the Self-Defense Forces: The Amphibious Brigade's Pledge

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(Read the report in Japanese.)

Authors: Toyohiro Ichioka, Keita Ozawa, and Naoki Otake, The Sankei Shimbun

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