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Japanese escort ship and US aircraft carrier

Bonds Across the Sea: The Story of the Japanese Navy and the U.S. Navy

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Respect and cooperation between Japan and the United States seen in the founding of the Japan Maritime Self-Defense Force

My grandfather was an officer in the Imperial Japanese Navy.
He was on a minesweeper and never saw direct combat with the U.S. Navy, but of the approximately 200 minesweepers the Imperial Japanese Navy had, only about 40 survived the war.
After the war, the surviving minesweepers and their crews were tasked with clearing the vast number of naval mines the U.S. had laid in Japanese waters.
This is a story about the former Imperial Japanese Navy and the U.S. Navy.

Table of Contents

During the Pacific War, the U.S. and Imperial Japanese navies fought a brutal conflict. Yet, only a few years after the war’s end, the former enemies became allies, with the U.S. Navy providing significant support for the reconstruction of Japan’s maritime defense capabilities.
This historical shift was driven not only by the political and military demands of the Cold War but also by a foundation of mutual respect that transcended the battlefield and a universal human trust.
This story will delve into the historical backdrop of the Japan Maritime Self-Defense Force’s founding, unraveling its complex development and the deep bonds that were forged across the ocean.

Part 1: The First Steps of Rebuilding – Between Collapse and Revival

The end of World War II left a complete void in Japan’s maritime defense capabilities.
On November 30, 1945, the Ministry of the Navy, the central authority of the Imperial Japanese Navy, was abolished and its organizational functions ceased.
In the chaos of the postwar period, the former navy’s duties were taken over by the Second Demobilization Ministry, primarily focusing on repatriation and the critical task of sweeping the tens of thousands of mines laid around Japan.
During this time, Japan’s naval power effectively disappeared, creating a situation known as the “maritime blank.”
However, this minesweeping work played a vital role in preserving the specialized knowledge and skills of former Imperial Navy personnel, which would prove indispensable for the later founding of the Japan Maritime Self-Defense Force (JMSDF).
The minesweeping duties were subsequently transferred to the Japan Coast Guard, established in 1948 as an external bureau of the Ministry of Transport.

A turning point for the revival of Japan’s maritime defense was the outbreak of the Korean War in June 1950.
The U.N. forces, with the U.S. at their core, found it difficult to spare enough troops for Japan’s defense as the front lines expanded, making the reconstruction of Japan’s own defense capabilities an urgent issue.
Under the directive of the Supreme Commander for the Allied Powers (GHQ), the National Police Reserve was first established as a land-based defense organization.
At the same time, the Japan Coast Guard, at the request of the GHQ, undertook a top-secret mission, dispatching a special minesweeping unit – comprised mainly of former Imperial Navy personnel – to the waters near the Korean Peninsula.
Despite suffering casualties in a mine detonation incident off Wonsan, they successfully completed their mission and earned high praise from the U.S.
This practical experience during the Korean War and the expertise of former servicemen honed through minesweeping became the first step toward rebuilding Japan’s maritime defense.

At the time, Japan’s political leaders were grappling with strong internal conflicts over rearmament.
Prime Minister Shigeru Yoshida, in particular, was adamantly opposed to rearmament before the signing of the San Francisco Peace Treaty.
He argued that Japan lacked the economic foundation to maintain modern military capabilities and that rearmament would risk collapsing the national economy and creating social instability.
His views reflected the harsh postwar reality that Japan’s security depended more on civilian stability than on military buildup.
However, during a meeting with U.S. Secretary of State John Foster Dulles, he was strongly persuaded that Japan’s military production capacity and labor force should be used to “strengthen the power of the Free World.”

A deeper look into this historical context reveals that Japan’s rearmament was not decided by a single factor.
It was the result of a complex interplay between strategic pressure from the U.S. to “strengthen the Free World’s defense capabilities” and Japan’s domestic goals of “economic stability and sovereignty restoration.”
The minesweeping operations in the Korean Peninsula earned the trust of the U.S. and paved the way for Japan to assume responsibility for its own security as an independent nation.
This shows that the founding of the JMSDF was not merely a passive response to U.S. requests but a proactive and complex political maneuver concerning Japan’s postwar independence and security.

Part 2: U.S. Navy’s Support and the Birth of the JMSDF

The reconstruction of Japan’s maritime defense capabilities was accelerated by tangible support from the U.S.
In October 1951, Prime Minister Yoshida accepted an offer from General Matthew Ridgway, the Supreme Commander for the Allied Powers, to lease patrol frigates (PFs) from the U.S. Navy.
This offer was more than just a provision of equipment; it was the first step toward an organizational reconstruction.

To accept this loan and establish an operational system, the “Y Committee,” a body of former Imperial Navy officers and Japan Coast Guard officials, was established directly under the Cabinet.
This committee was a platform for bringing together the expertise of specialists who had been studying naval reconstruction since the war’s end. Its purpose was not only to operate the vessels provided by the U.S. but also to build the foundational structure of a new organization, including personnel recruitment, training, and the establishment of a salary system to maximize the capabilities of the ships.
This signified that the U.S. support was not just a transfer of “materials” but the provision of a “system” for creating a new maritime defense organization from the ground up.

These efforts culminated in the legal framework established by the Mutual Defense Assistance Agreement (MSA) signed in 1954.
This agreement, based on the U.S. Mutual Security Act, obligated Japan to strengthen its own defense capabilities.
In the same year, the “Defense Agency Establishment Law” and the “Self-Defense Forces Law” were enacted.
This led to the formal establishment of the JMSDF on July 1, 1954, following the creation of the Coastal Safety Force (established in 1952) and the National Safety Agency’s Guard Force.

Under the “Agreement Concerning the Loan of United States Naval Vessels to Japan” signed simultaneously with the MSA Agreement, numerous vessels were provided by the U.S. to Japan.
These ships formed the backbone of the nascent JMSDF’s power and were essential for Japan’s reconstruction of its maritime defense capabilities.
The scale and types of vessels provided specifically demonstrate the challenges the JMSDF faced at the time and the extent of the support the U.S. offered.

Class of Ship	Number of Ships	Notes
Destroyers	4 ships	Formed the core of the early escort fleet
Destroyer Escorts	2 ships	Contributed to anti-submarine patrols
Submarine	1 ship	Contributed to the rebuilding of submarine capabilities
Minesweepers	7 ships	Continued the crucial postwar mission

As this table shows, U.S. support clearly illustrates that the early JMSDF was built on two wheels: the “human resource” of former Imperial Navy expertise and the “material resource” of ships provided by the U.S.
This goes beyond the abstract fact that there was “cooperation” and shows that the cooperation was practical and specific, an important element in reinforcing the report’s credibility.

Part 3: Respect Across the Ocean – A Story of Bushido and Friendship

When discussing the maritime relationship between Japan and the U.S., it’s impossible to ignore the human bonds that were forged between the two navies.
It was a story of universal respect and friendship that transcended the political interests of the Cold War.

A symbolic episode is the story of the heavy cruiser USS Indianapolis and the Imperial Japanese Navy submarine I-58.
In July 1945, after completing a top-secret mission to transport atomic bomb components, the Indianapolis was torpedoed and sunk by the I-58 while sailing off Leyte. Months after the tragedy, Captain Charles B. McVay III was court-martialed for failing to zigzag his course and putting his ship at risk, for which he was convicted.

In an astonishing turn of events during this unprecedented trial, the commander of the I-58, Lieutenant Commander Mochitsura Hashimoto, testified in a U.S. court on behalf of Captain McVay.
Based on his observations at the time, Hashimoto stated that he “could have sunk the Indianapolis even if it had been zigzagging” and offered his opinion that the sinking was not McVay’s fault.
This testimony was not born of personal sympathy but was a statement of objective tactical truth as a submariner and a professional naval officer.

Hashimoto continued his efforts to clear McVay’s name, and his actions were called “the Bushido of the Sea.”
McVay suffered under the weight of his conviction and tragically took his own life in 1968.
However, due to the decades-long efforts of Hashimoto and others, the U.S. Congress passed a resolution in 2000 clearing McVay’s name and officially recognizing him as “exonerated for the loss of the Indianapolis.”
Tragically, Hashimoto, who had dedicated the latter half of his life to restoring McVay’s honor, died just five days before the resolution was enacted and never heard the news.

This episode shows that a deep respect, based on a shared identity as naval officers and professionalism, existed between the former enemies. Lieutenant Commander Hashimoto’s action – objectively and professionally denying the fault of an enemy commander – was the epitome of a military officer’s honor and a symbolic event that shaped the spiritual foundation of later U.S.-Japan cooperation.

Furthermore, a similar respect existed among top commanders and soldiers on the ground.
Admiral Chester Nimitz, Commander-in-Chief of the Pacific Fleet, strictly ordered all forces to refrain from attacking the Imperial Palace to facilitate a smooth occupation after Japan’s surrender.
This decision was based not only on military considerations but also on an understanding of Japanese culture and history.
Like Nimitz, Admiral Raymond Spruance, known as the victor of the Battle of Midway, is also said to have held a deep respect for Admiral Heihachiro Togo of the Imperial Japanese Navy, whom he met during a visit to Japan in his youth.

On a personal level, even more human-centered exchanges took place. There is an episode from the postwar period when former Japanese soldiers visited Iwakuni Air Base and interacted with active-duty U.S. military personnel.
One former Japanese soldier recounted that he was harassed by a U.S. Marine on a train, fought back, and was court-martialed.
The Marine admitted his own fault in court, and the Japanese soldier was released.
The former soldier then invited the Marine to his wedding.
Such stories of reconciliation and friendship that transcended hostile relations show that a stronger human bond existed, separate from political ties between nations.

These episodes illustrate that the U.S.-Japan alliance was not built merely on a political and military alignment of interests during the Cold War.
It was rooted in a profound, historically nurtured spiritual foundation where military personnel from both nations – from top strategists to frontline soldiers – respected each other’s professionalism and humanity.

Part 4: Toward a Stronger Alliance – A History of Continued Cooperation

The U.S.-Japan cooperation that began during the founding of the JMSDF has deepened and diversified in modern times.
While the early days were characterized by tangible aid like vessel leases based on the MSA Agreement, current joint exercises aim for more advanced and integrated collaboration.

The U.S. and Japanese navies have actively conducted joint exercises in recent years.
An example is the first joint anti-submarine training in the high seas of the South China Sea, which is seen as a way to deter a specific country that is militarizing the area.
Moreover, multilateral maritime cooperative activities (MCA), including with the Philippine and Australian navies, are regularly conducted, building a multi-layered cooperative system to ensure regional stability.
These exercises are not merely shows of friendship; they aim to enhance “interoperability” at a practical level concerning doctrine, tactics, skills, and procedures.

Conclusion

The founding of the Japan Maritime Self-Defense Force is a story of Japan’s sovereignty restoration and security, realized amidst the complex intersection of postwar international relations and domestic politics.
The U.S. Navy’s support was not just material aid but a comprehensive provision of a system to rebuild a maritime defense organization.
This cooperative relationship was rooted in a solid spiritual foundation of deep mutual respect and human friendship that transcended the battlefield, as symbolized by the story of the Indianapolis and I-58 commanders.

Understanding this historical context is the most fundamental answer to the question of why the U.S.-Japan alliance remains so strong today.
It was not built on a relationship of convenience or one-sided aid but has been cultivated by a timeless shared value of professionalism and respect for universal humanity.
The close cooperation between the modern U.S. and Japanese navies and their joint contribution to stabilizing the international order are the fruition of this historical accumulation of trust.