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Dongame: Japan's Submarine History and Challenges

By Vice Admiral Kazuki Yano, JMSDF
Commander, Fleet Submarine Force

The Japanese Maritime Self Defense Force (JMSDF) and its predecessor, the Imperial Japanese Navy (IJN), have long used the term dongame (“languid turtle”) to encapsulate the unique nature of conventional submarines. They possess the contrasting characteristics of offensive strength combined with poor underwater maneuverability. Japanese Submariners have continued to use the term with great pride and lighthearted self-deprecation. Of course, conventional submarines and antisubmarine platforms have continued to evolve; notably, there are significant gaps in undersea maneuverability and detection capability between conventional and nuclear powered submarines. In this article, I would like to briefly explain dongame, the evolution of the Japanese submarine force, and our future challenges.

The History of Dongame
The IJN Submarine Force took its first step in 1905, four years after the birth of the U.S. Submarine Force. The Japanese Navy purchased materials for five Holland-class submarines from a U.S. company, Electric Boat, for service in the Russo-Japanese War, which had broken out the previous year. The submarines were quickly assembled at the Yokosuka shipyard and all were commissioned in October 1905. However, the war ended before they could take part in any action. The first U.S. submarines were also of the Holland class; the U.S. and Japanese Submarine Forces evolved from the same point of origin. Subsequently, the IJN made progress by absorbing technologies from England, France, and Germany.

During the Pacific War, submarine warfare was waged relentlessly and IJN operational submarine doctrine contributed by attriting the adversary’s principal combat power. However, operational errors were committed which led to the loss of lives and no consideration was given to technological reforms or submarine production. The tactics, technology, and production capacity of the Allies’ antisubmarine platforms decisively overwhelmed Japan. Despite these aggressive Allied antisubmarine warfare (ASW) efforts and chronic equipment shortages in the IJN Submarine Force, Japanese Submariners fought well by leveraging the unique characteristics of the submarine.

Established seven years after the end of the war, in 1952, the JMSDF was tasked initially with an ASW mission. In January 1955, Japan acquired one submarine from the United States for service as a target ship. A crew composed primarily of former IJN submariners was sent to New London, Connecticut for training. Having been trained, the crew transferred to the Gato-class submarine ex-USS Mingo (SS 261), which was re-christened JDS Kuroshiro (SS 501). With the safe arrival of the crew and the submarine in Japan, the history of the Japanese Submarine Force resumed after the 10-year gap following World War II.

JDS Harushio (SS 583) Photo by JMSDF

Soon after, Japan started to domestically produce submarines. In 1960, Kawasaki Heavy Industries (Kobe), a pre-war submarine manufacturing company, built JDS Ōshio (SS 561), the first domestically produced submarine since the end of the war. Mitsubishi Heavy Industries (Kobe) also produced submarines. Together the two companies strengthened and maintained Japan’s domestic submarine production capability, building approximately 50 submarines up to the present day. The 1977 Defense Guideline called for 16 submarines for the defense of critical straits. To meet this requirement in 1971, with remarkable advances made in underwater detection and maneuverability, the JMSDF commissioned its first teardrop-shaped submarine, JDS Uzushio (SS 566), modeled after the U.S. Navy’s Barbel class. Successively, the JMSDF continued to make advances one step at a time, including improved quieting on the Harushio class, side arrays for improved detection on the Oyashio class, and Stirling AIP propulsion for improved maneuverability on the Soryu class.

In 1981, the Submarine Force was formed with two submarine groups and a Submarine Training Center (STC); it was the only Force in the JMSDF to have a fleet school. STC was charged with training and tactical development along with submarine training support and combat systems integration. In this way, the STC sustains the foundation of the Submarine Force. Operationally, we have maintained a strong partnership with the U.S. Navy since 1963, dispatching a submarine each year to Hawaii to receive training and mentorship. Since 1986, Japanese submarines have participated in RIMPAC. Furthermore, we conduct passing exercises (PASSEX) in the waters surrounding Japan, as well as various other training exercises that enhance our great partnership.

Challenges for Dongame
As we have seen, the JMSDF Submarine Force was established with wide-ranging support from the U.S. Navy Submarine Force, and we continue to mature with their operational and technological support.

Nevertheless, technological support from the U.S. Submarine Force will necessarily be limited, as it specializes in nuclear submarines. The JMSDF Submarine Force will, in some ways, have to depend on domestic support for its further development.

At the end of the last fiscal year, a decision was made in the Japan Defense Guidelines to increase the number of submarines from 16 to 22. Considering the current fiscal environment in Japan, for this plan to go forward without debate is extraordinary. I interpret this as the people of Japan placing confidence in their Submarine Force. For this reason, the Submarine Force must commit the whole Force to this endeavor to meet mission requirements. Going from 16 to 22 submarines will increase our footprint by 40 percent, clearly enhancing operational freedom. Even the increase to 22 submarines may not be enough considering the size of our area of operation. The current national security environment in which Japan finds itself requires submarines with enhanced capability. Without capability improvements, a simple increase in force structure will be insufficient. Obviously, the increase will pose challenges in the critical area of crew training and development. We are implementing policies to accelerate promotion for those wearing dolphins, and STC is well postured for training new students. We are strongly committed to addressing these issues and keeping our Sailors aware of them.

JDS Uzushio (SS 566) Photo by JMSDF

There are myriad other issues that need to be solved from the acquisition of new ammunition, to improving supply and mooring facilities, to ensuring higher operational availability by standardizing maintenance. The development of the Soryu-class next-generation submarine also presents us with a predicament. We must consider the kind of capability required for the next generation submarine and how and where it will operate with U.S. Navy submarines. The Submarine Force needs to come together, give serious consideration to these issues as military professionals, and think about what we must ask of our scientists and engineers.

We will maintain close relationships with domestic institutions such as weapons/submarine producers, shipyards, the Dive/Hyperbaric Medicine Unit, and the Technical Research and Development Institute. We have seen good things come from these relationships, as well as some negative impacts, but undeniably they have helped improve the Japan Fleet Submarine Force. The military professionals of the Submarine Force recognize that these domestic partners are all on the dongame team. As such, uniformed, civilian, and private and public sector personnel need to come together in order to exchange candid views, foster good relations, and face these challenges in a unified effort.

Our modern Submarine Force is a product of the hard lessons learned by the IJN Submarine Force in World War II as well as the continued support of the U.S. Navy. We teach the students at STC to make every decision as if they were in combat. In addition, at the entrance of STC is a motto borrowed from the U.S. Navy —“Know Your Boat”—and a reminder: “We are at the Center of Battle.” Energized by these mottoes, we also take pride in the fact that during the Cold War Japan was one of the few nations in Asia to gain experience in submarine operations.

The current Submarine Force has inherited the DNA of those past dongame. An illustrious past will not always lead to success in the future, but our foundation is unshakable. Submarining is a challenging business, and many challenges still exist in submarine operations, systems, and training. The undersea warfare potential of the JMSDF Submarine Force will remain strong as long as we sincerely acknowledge these issues and continue to put forth the effort to make improvements and innovations to our submarines. I believe that sustaining these efforts and enhancing combat capability will play an important role in our national security and moreover are prerequisites to maintaining a close partnership with the U.S. Navy’s Submarine Force.