Earlier this year, The Strategy Bridge asked university and professional military education students to participate in our third annual student writing contest by sending us their thoughts on strategy.

Now, we are pleased to present one of this year’s third-place essays by Phillip Ramirez from the U.S. Naval Postgraduate School.

The resource-poor nations of the United Kingdom and Japan have often relied on water as a lifeline, bringing food and raw materials to fuel their people and manufacturing bases while serving as a conduit through which the nations can export their finished goods to eager overseas markets. Therefore, when those life-lines were targeted by their enemies in the World Wars using the greatest trade interdiction weapon yet created—the submarine—both the United Kingdom and Japan were nearly immobilized. For the United Kingdom, the German submarine threat nearly lost them both World Wars. For Japan, the American submarine threat proved to be a decisive factor in its defeat. No two other countries have been targeted in such a way during wartime, and no two other countries have been forced to respond to such an existential threat from the sea.

However, while the United Kingdom and Japan experienced similar threats and had similar strategic needs, their responses were astonishingly different. Each country’s response to the submarine threat can be broken down into two separate but interrelated phases: first, the degree to which each country was prepared to counter the threat to their maritime trade at the outbreak of the war, and, second, the ability of each country to respond to the threat once it had presented itself during the war. With respect to the first phases, the reigning strategic doctrine at the time, namely the idea that conflicts would be decided in one Mahanian naval battle, guided the strategic outlook of each country, massing their fleets for battle battle as opposed to protecting the vital shipping lanes. With respect to the second phase, it seems the United Kingdom possessed what Japan did not—an effective check on military leaders in the form of civilian oversight of the military that both balanced the military’s natural conservative tendencies and corrected the military when it had erred. Ultimately, it was the delicate balance of civil-military relations that saved the day in the United Kingdom and doomed the Japanese Empire to defeat.

The United Kingdom in 1917

During World War I, the Germans utilized unrestricted submarine warfare in two distinct phases: first between February and August of 1915 and again between February of 1917 and the end of the war in November of 1918.[1] The first period of unrestricted submarine warfare ended with the sinking of the Lusitania. The second period of unrestricted submarine warfare had its beginnings in the Battle of Jutland in 1916, after which the German naval staff came to believe that even a decisive victory over the Royal Navy would have little effect on the war’s outcome.[2] Therefore, in January of 1917, the German naval staff recommended the recommencement of unrestricted submarine warfare, confident the strategy would cripple the British war effort and force them to sue for peace before the United States could apply its military power to the Entente’s side.[3] As such, on January 31st, 1917, the Germans declared an unrestricted war zone around the British Isles, parts of France, and in the Mediterranean Sea.[4]

During the three months prior to the onset of this second phase of unrestricted submarine warfare—November 1916 to January 1917—the German U-boats had managed to sink an average of 130,000 tons of shipping each month.[5] As Arthur Marder, author of the seminal work on the Royal Navy during World War I, notes, the numbers began to dramatically increase, starting with the sinking of 464, 599 tons of British, Allied, and neutral shipping (209 ships) in the month of February 1917 alone.[6] In the following two months, the situation became even more desperate. Submarines sank 507, 001 tons of shipping (246 ships) in March 1918 and an astonishing 834, 599 tons of shipping (354 ships) in April 1918, much of the tonnage in the latter month being sunk between April 17th and April 30th in what has come to be known as the “Black Fortnight.”[7]

Seeing the dramatic results of the German’s unrestricted submarine warfare campaign, the British were forced to change their strategy to counter the German U-boats. Before April of 1917, the British had employed several unsuccessful operations to deal with the U-boat menace: the distant blockade of the High Seas Fleet; U-boat search and destroy forces; the dispersion of shipping, namely by sending merchant ships to sea one at a time and on routes prescribed by the Admiralty; and the arming of merchantmen.[8] However, when the shipping losses became too much to bear, the British admiralty decided to switch to a convoy strategy. As Marder describes it, the convoy system is the practice of sending merchant ships to sea in large, organized groups under the protection of one or more warships, the idea being that the merchant ships can be more easily protected in a group and that the group itself, in the vastness of the oceans, would be no easier to find that a single ship. [9] Although the convoy system took time to demonstrate its value—shipping losses in June 1917 were still high at 544, 096 tons, but this can arguably be attributed to the slow implementation of the system—the concept paid off in the long run.[10] By November of 1917, losses had dropped to 259, 251 tons and the British Admiralty confidently declared “the U-boat menace ‘would be well in hand by the spring of 1918.’”[11]

The Japanese Empire from 1941 to 1945

Like the United Kingdom during World War I, when the Japanese Empire began fighting the Allied nations in 1941, the country’s planners did not predict the eventual threat the submarine would pose to its ability to wage war. Unlike the United Kingdom, the Japanese did not have the convenient excuse of being the first to encounter such a threat. Despite the haunting clear parallels, the Japanese failed to learn the lessons of British experience during World War I. Throughout that war, the Imperial Navy was involved in escorting Entente shipping convoys throughout the Pacific and Indian Oceans, and, at the end of the war, the Imperial Navy even escorted convoys in the Mediterranean Sea.[12]

The Japanese situation was not helped by the fact that, even at the beginning of the war, the country did not possess an adequate amount of shipping to keep itself fully supplied. One estimate determined that the Japanese required ten million tons of domestic shipping to meet their needs, but, at the outbreak of the war the country only possessed six million tons.[13] Before the war, the remaining four million tons of shipping had to be made up by foreign ships, mostly vessel that flew the flags of the nations against which the Japanese had declared war.[14] This situation was compounded by the fact that the Japanese relied on the import of raw materials and food to fuel its growing industrial base and its impressive war machine. Indeed, the drive for resources such as oil, tin, rubber, and iron was one of the central reasons (if not the central reason) the Japanese declared war on the Allied nations in 1941.

The United States’ campaign of unrestricted submarine warfare was eventually effective in denying the Japanese their prizes from the Southern Resource Area. Japanese shipping losses in 1942 totaled 977,927 tons, an average of roughly 81,500 tons per month.[15] In 1943, the number skyrocketed, nearly doubling to a total 1,767,642 tons, and in 1944 the number more than doubled again, totaling 3,823,485 tons for the entire year.[16] In 1945, the U.S. managed to sink an additional 1,809,194 tons between the start of the year and the Japanese surrender, but by that time there was not much left to sink; the Imperial Navy was all but obliterated and what was left of the merchant fleet was in port for repairs or stranded there by mines.[17] While the absolute numbers seem miniscule when compared to British shipping losses, the amount of shipping sunk relative to the amount of shipping with which the Japanese began the war is almost incomprehensible. The Japanese began the war with 6,384,000 tons of merchant shipping and ended it with less than a quarter of that—1,466,900 tons.[18]

Unprepared and Unaware: Explaining the Lack of Anti-Submarine Warfare in the UK and Japan

What is so striking about both the British and the Japanese cases was that both countries seemed so unprepared and unaware of the challenges the submarine might present. For the British, this oversight is excusable. For the Japanese, it is not. However, fundamentally, both countries relied on overseas trade to such an extent that logic would dictate that each country should have focused on protecting their trade, presenting an interesting puzzle as to why neither country did so. The answer to this puzzle can be found in the underlying strategic doctrine that both the British and the Japanese, either for choice or by force, adopted at the time.

Offensive Thought in the UK

The British Navy during World War I, whether by choice or by circumstance, became slave to a combination of misapplied Mahanian doctrine and a bias for the offensive. By the dawn of the twentieth century, the British had been forced to consolidate their ships around the British Isles in response to the threat of growing German High Seas Fleet. While the British understood the totality of Mahanian doctrine—essentially that a nation’s fleet and maritime trade were inseparable, with the former protecting the latter and the latter strengthening the former—the Germans did not. The Germans embarked on their massive naval construction program at the end of the nineteenth and beginning of the twentieth century with the vision of creating a fleet large enough to deter the British from entering a continental war, or, short of that, large enough to win a decisive naval battle against them in the North Sea.[19] This idea of the decisive naval battle has its beginnings in Mahanian doctrine. Mahan theorized that future conflicts would be decided by a decisive naval battle between two opposing fleets. Therefore, fleet concentration was critical; nations needed to concentrate their fleets so that, when the time of the decisive battle came, each side would be able to muster the full strength of their navies. While the British did not explicitly attempt to do this, the Germans certainly did, and the British had no choice but to consolidate their fleet to prepare for the decisive battle the Germans envisioned.

The British adherence to these ideas manifested themselves in two important ways during the war. First the British Admiralty was reluctant to separate their destroyer escorts from the fleet. One of the main arguments put forth by the British Admiralty against the adoption of the convoy system was that the number of ships required to protect the convoys was far too high and would detract from the Royal Navy’s ability to support other fleet actions, namely the ability of the Grand Fleet to effectively fight the High Seas Fleet. Marder writes that Admirals John Jellicoe and David Beatty—the First Sea Lord and Commander-in-Chief of the Grand Fleet, respectively— “regarded the denuding of the Grand Fleet still further from its indispensable destroyer escort, without which it could not move, as too hazardous a gamble.”[20] In fact, according to Marder, the British possessed enough escorts to simultaneously implement a convoy system and protect the Grand Fleet. The problem lay not in the number of ships but in the way in which the appropriate number of escorts was calculated, as the British naval staff falsely believed convoys would require two-times more escorts than were actually necessary. [21]

This incorrect calculation was also affected by the second outcome of the Royal Navy’s adherence to misused Mahanian doctrine: the British Admiralty’s preference for the offensive. In addition to miscalculating the number of escort vessels needed for the convoy system, the British naval staff also accounted for the amount of escort ships needed to continue search and destroy operations against U-boats, failing to realize that the convoy system and such operations were alternatives not complements.[22] This demonstrates the Royal Navy’s bias for operations they deemed offensive and distaste for operations they deemed defensive. The British Admiralty considered patrols one of the former and convoys one of the latter. As the late Peter Gretton, a former convoy commander himself during World War Two and a senior research fellow at Oxford University, writes, “The patrol, however useless it was, gave an impression of ‘doing something.’ It was considered offensive and it gained a certain cachet.”[23]

Offensive Thought in Japan

Japanese thought before World War II was also focused on the Mahanian idea of the decisive battle and on the cult of the offensive, but, unlike the British, the Japanese were not forced into this situation by another major power. On the contrary, the Japanese adopted Mahan wholesale, but, like the Germans, mistook its central lessons, concentrating on one central element—the decisive battle. Nowhere is this more obvious than in the operations of the Imperial Navy. From Midway to the Philippine Sea, to the sea around Saipan and the Battle of Leyte Gulf, the Imperial Navy never gave up on the idea of the decisive battle, allowing it to remain in their minds “until they had no navy left.”[24] As Mark P. Parillo, Associate Professor and Kansas State University and author of The Japanese Merchant Marine in World War II, so aptly summarizes, “The misapplied doctrines of Alfred Thayer Mahan loomed over the Imperial Navy’s strategic thought like no other influence in its history.”[25]

This misplaced faith in the decisive battle had two effects in relation to the Japanese response to the U.S.’s unrestricted submarine warfare, both of which contributed to the inability of the Japanese to effectively prepare for the submarine threat. First, because of the focus on the main battle fleet and the strength of its capital ships, the Japanese focused their limited resources on constructing ships for the main battle fleet, diverting resources away from civilian construction of merchant shipping. This trend was evident from the birth of the Japanese Navy, and it seems to have been a part of the country’s rapid industrialization. The Japanese government provided subsidies to help nurture a growing shipbuilding industry, which had the effect of creating an impressive industry in a few decades. Simultaneously, though, that industry became focused on naval projects as opposed to civilian merchant ship construction, as naval contracts helped fund shipbuilding in times of depression and never let up in boom times.[26] Parillo estimates that Japanese shipyards were able to produce an average of 400, 000 tons of naval warships annually during the last five full fiscal years before the war, but less than half that figure in terms of merchant shipping.[27] Essentially, naval shipbuilding squeezed out all other types of shipbuilding in civilian yards, leading to a gap in Japanese shipping capacity and Japanese shipping needs.

Aside from diverting resources away from projects that would positively affect the ability of the Japanese Empire to sustain its maritime trade, the focus on the decisive battle produced a navy that was both imbalanced and dangerously thin. Nowhere is this trend more obvious than in the massive super-battleship projects. Each of these ships, and the Japanese built three, took three years to construct and another two years to outfit.[28] On the other hand, between 1941 and 1943, the Japanese did not launch a single destroyer escort.[29] This emphasis on large capital ships affected not only production but the very ability of the Imperial Navy to fight a sustained war at sea while simultaneously protecting its valuable merchant fleet. Indeed, while the initial strength and capability of the Imperial Navy was impressive, there was little to replace it with when it failed.[30] As one scholar aptly concludes, “The Imperial navy was so finely tempered, it was brittle.”[31]

Intra-War Learning: Why the UK learned and the Japanese Lost

It is clear from the previous discussion of the disposition and mentality of the Royal and Imperial Navies in the years leading up to the war were not all that different. Both adhered to what can be termed the cult of the offensive, preferring offensive action over its defensive counterpart, and both, either through choice or circumstance, were forced to adhere to the idea of the decisive battle. Therefore, the difference that allowed the British to adopt an effective response to the submarine threat and the inability of the Japanese to do so must be found in the actions that took place during the war, and indeed it is. The key factor, which brought the British victory and the Japanese a premature defeat, was a difference in each country’s civil-military relations.

Civilian Dominance in the United Kingdom

Until the end of April 1917, the British Admiralty was emphatic that the convoy system would not work. Marder characterizes their main arguments against the system. First, too many convoys would be necessary to provide support and supplies for the several different fronts of the war. Second, vessels would be too long delayed waiting for convoys in ports, especially those that were supposed to run on fixed schedules. Third, ports would cycle through dearth and overload as convoys entered and exited ports. Finally, slow vessels in the convoy would slow down faster ones.[32]

But, for each of the British Admiralty’s arguments, there was an even stronger rebuttal. Most of the ships involved in trade were exclusively coastal traders; the actual number of ships engaged in overseas voyages was low and could easily be escorted in convoys. Most ships were already significantly delayed, kept in port because of U-boat sightings by patrol craft, a state of affairs that also meant ports were either already full of ships or contained none. Finally, the avoidance tactics that merchant ships employed on their routes were already doubling the length of some voyages.[33] Yet, despite the logic of these arguments, the British Admiralty obstinately remained “a conservative institution” until the bitter end.[34]

That end came with the intervention of higher powers who were able to check the unwillingness of the Admiralty in two distinct ways: first through direct intervention on the part of Prime Minister David Lloyd George, and second through a correction of a naval statistical error by the Ministry of Shipping. As shipping losses continued to mount, civilian authorities, specifically Prime Minister Lloyd George, began to take a keen interest in what could be done to avert them. He was finally spurred into action in April when the shipping “situation was accelerating in the wrong direction at an increasingly record rate.”[35] Indeed, based on the figures, the British and their allies lost 881,027 tons of shipping that month (including those losses not due to submarine activity), which represents an increase of 287,186 compared to the previous month and a change in acceleration of 233,351 tons as compared to the previous month. In short, the situation was bad and getting worse.

In response to the dire straits in which the country now found itself, Prime Minister Lloyd George, on April 25th, 1917, informed the British Admiralty that he would personally visit them—a heretofore unprecedented step—on April 30th to discuss the issue of the convoy.[36] It seems that this demonstration of authority, “the prospect of being overruled in their own sanctuary,” as Lloyd George himself put it, forced the Admiralty to adopt to convoy system.[37] By the time the Prime Minster arrived to meet the British Admiralty, they had already made up their minds to adopt the convoy. In fact, three days before the Prime Minister’s visit, the Admiralty had given orders to begin a trial convoy from Gibraltar. [38] This information raises the question of if it was truly the Prime Minister’s impending visit that changed the Admiralty’s minds. Marder believes it was not, citing an April 26th memorandum by Admiral Sir Alexander Duff, head of the Anti-Submarine Division of the Naval Staff, which advocated for the immediate introduction of the convoy system and seems to have swayed the rest of the Admiralty.[39] Up to this point, Admiral Duff had been a staunch opponent to the convoy system, so the question to be asked is what exactly changed his mind. There seems to be two plausible answers. First, it does not seem coincidental that the memorandum was written the day after Prime Minister Lloyd George announced his intention to visit the Admiralty. As one scholar, states so eloquently, “I cannot believe that this deathbed repentance was entirely fortuitous.”[40] Even if it was, evidence indicates that Duff’s convictions were not simply changed by the dramatic increase in the rate of shipping losses, but by the second civilian intervention in the matter of the convoy—a statistical correction issued by the Ministry of Shipping.

The statistic in question concerned the amount of shipping that would have to be protected by escorts in order to successfully implement the convoy system. The British Admiralty had come to believe that the number of merchant vessels entering or leaving a U.K. port in a single week was 5,000 and were publishing reports that said as much.[41] However, the Admiralty was not looking at the right numbers. The 5,000 ships per week figure included vessels that traveled along the coast and across the English Channel. When only ocean-going vessels were counted, the number became much more manageable—120 to 140 vessels arriving and the same number leaving each week.[42] Under these circumstances, the prospects of a convoy became much more manageable in the Admiralty’s eyes. Indeed, Admiral Duff received these corrected statistics from an officer on his staff at the Anti-Submarine Division, Commander Reginald Henderson, who in turn had received the information from the Ministry of Shipping with which he had worked closely in coordinating coal convoys from France.[43] Whether it was Prime Minister David Lloyd George or staff members at the Ministry of Shipping, it seems clear that civilian oversight of the military saved the day.

Military Dominance in Japan

If the United Kingdom was saved by the civilian oversight of its military, the Japanese Empire was doomed by the lack of such oversight. That said, there is no doubt that the Japanese would have lost World War II, even if they had managed to foresee the necessity of developing a well-balanced navy and a merchant fleet large enough to meet their needs. Fundamentally, Japanese strategy relied on the assumption that the German war machine would not be stopped and the allies would therefore have no choice but to accept the Japanese conquest as a fait accompli. Barring that outcome, the Japanese would have gradually been overpowered by the industrial might of the United States and her allies. Therefore, any Japanese action to improve its maritime shipping capacity during the war would have been an effort to avert losses and to maximize efficiency in order to prolong the war.

Such an outcome was all but closed off by the state of civil-military relations in Japan both before and during the war. In fact, it is not outlandish to say that the traditional roles were actually reversed. Save for the limited but revered authority of the emperor, there were no formal checks on the military’s decision-making since the 1889 constitution did not subjugate it to civilian control.[44] As such the military expanded into almost every facet of Japanese decision making, both in wartime and in peacetime. Both the Army and the Navy withheld crucial figures on warship tonnage and fuel reserves from the civilian cabinet, preventing their civilian counterparts from gaining an accurate picture of the country’s situation both before and during the war.[45] In the early days of the war, the military was able to gradually take over the country’s industrial base, assigning junior military officers as resident inspectors, subverting the control of more knowledgeable and better qualified government bureaucrats and plant managers.[46]

Politically, the military’s free hand was even more disruptive. Military intervention in political affairs led to a series of assassinations and coups in the early and mid-1930s and put Japan on the path to war. In one of the most dramatic episodes—known as the “Manchurian Incident” —the Imperial Army invaded and occupied the Chinese province of Manchuria completely of its own accord in 1931, forcing civil authorities to formally recognize the occupation of the province.[47] Emboldened by their success, the Imperial Army again acted of its own accord in the “China Incident,” beginning a full-scale war against China and setting the stage for the Japanese war against the Allies.[48]

The complete lack of civilian checks on the military not only hamstrung what could have been a viable avenue of reform, but led to a concurrent problem—an intense, adversarial rivalry between the Army and the Navy. Rivalry is too weak of word; by many accounts, the Army and Navy regarded each other as the true enemies, even during the war, going so far as to erect defenses around their ministry buildings in case the other service tried to take over.[49] The rivalry likely grew as a result of the ability of the military to take over certain aspects of civilian affairs—leading to a competition between the Army and Navy as to which one could accrue the most power—and as a result of the lack of any formal organization to oversee the services’ operations and arbitrate their disputes.

This dynamic had a disastrous effect on the efficacy of merchant shipping. Instead of a consolidated, efficient transportation command or ministry, each service operated its own shipping control offices.[50] The already meager supply of escort ships and aircraft were therefore divided between the two different shipping offices, neither of which had much incentive to pool resources, share information, coordinate convoys, or otherwise maximize the efficiency of the limited resources at their disposal.

In any case, what limited control the Army and the Navy did exercise over shipping and supply was not very effective. Empty merchant ships set sail to new ports to take on cargo only to arrive and see other empty ships sailing in the direction from whence they had come.[51] Forward progress was made only in March 1944, when the Japanese began implementing the convoy system and building up on anti-submarine force, but by that time it was too little, too late.[52] Other parts of the both the Army and the Navy, desperate for equipment, appropriated what limited aircraft and ships were assigned to escort duty, and the American submarines devastated their defenseless prey.[53] As such, the Japanese war effort collapsed. Frontline troops went without the necessary food and supplies to make an effective fighting force. On the home islands themselves, during the last months of the war, hunger and starvation became the most important issues of the day, forcing the government to devote what little shipping it had left to ferrying foodstuffs from China and Manchuria to the decimated Japanese Islands.[54] In the end, the Japanese were brought to their knees by the lack of shipping. The American submarine victory was utterly and totally complete.

Conclusion

The British and Japanese experiences with antisubmarine warfare and merchant shipping during World War I and World War II, respectively, could not have been more different. Both countries began their respective conflicts at a disadvantage with respect to their positions on maritime trade protection, instead concentrating their offensive capabilities and on their ability to bring enough force to bear to defeat the enemy in a decisive naval battle. The effects of this unpreparedness were stark. Both countries lost enormous amounts of merchant shipping throughout the war, and both countries were pushed to the brink of disaster. However, only one country fell over the edge. The British were able to develop effective tactics to stem the tide of destruction, whereas the Japanese merchant fleet was hunted to extinction. In the end, it was the institutions of civil-military relations that made the difference.

Civilian authorities in the United Kingdom, either through intimidation or bureaucratic independence, were able to convince the Royal Navy to adopt the convoy system, stemming the tide of the merchant fleet’s destruction. On the other hand, the unchecked power accorded to the Imperial Army and Navy in Japan produced a civil government incapable of standing up to the power of the military, forcing the civilian authorities to quietly acquiesce to the demands of the military. In addition to the lack of effective checks that could have forced a restructuring of the military’s antisubmarine strategy, the competition for influence and power led to an intense rivalry between the Army and the Navy, making cooperation between the two services on the issue of merchant shipping and escorts impossible. It was the inability to the civil government to check the military and arbitrate between the two services that ultimately doomed the Japanese Empire to a premature defeat.

The Japanese and British experiences with the management of their merchant shipping during wartime and their antisubmarine warfare efforts demonstrates the importance of installing a strong civil authority above the military. That being said, it cannot be denied that there have been episodes in which civil leaders have hamstring military operations, risking lives and material for the sake of politics or personal gain. But in the two largest wars this planet has ever experienced, the authority and influence of civilians over military affairs assured victory in one and the lack of such brought total and utter defeat in another. Therefore, in the grand scheme of things, civil control of the military has proven its value not only as an avenue for better governance, but as a strategic asset capable of providing the necessary leverage to achieve victory in wartime.

Phillip M. Ramirez is an officer in the U.S. Navy currently studying at the Naval Postgraduate School in Monterey, CA. He is currently writing a master’s thesis entitled “Power to Xi: How Xi Jinping Consolidated Political Power in the People’s Republic of China.” The views expressed are the author’s alone and do not reflect the official position of the Naval Postgraduate School, the Department of the Navy, the Department of Defense, or the U.S. Government.

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Header Image: “Sinking of the Linda Blanche out of Liverpool” (Kaperung und Versenkung des englischen Handelsdampfer Linda Blanche) by Willy Stöwer (Wikimedia)

Notes:

[1] Scott Sigmund Gartner, “Strategic Assessment in War,”(New Haven, CT: Yale University Press, 1997) 67.

[2] Daniel Moran, “The Great Disorder,” in Maritime Strategy and Global Order: Markets, Resources, Security, ed. by Daniel Moran and James A. Russel, (Washington D.C.: Georgetown University Press, 2016) 39.

[3] Peter Gretton, “The U-boat Campaign in Two World Wars,” in Naval Warfare in the Twentieth Century, ed. by Gerald Jordan, (London: Croom Helm, 1997) 128-129.

[4] Gartner, “Strategic Assessment in War,” 75.

[5] Gretton, “The U-boat Campaign in Two World Wars,” 128.

[6] Arthur Jacob Marder, From Dreadnought to Scapa Flow: The Royal Navy in the Fisher Era, 1904-1919, (Oxford University Press) 102.

[7] Marder, From Dreadnought to Scapa Flow, 146.

[8] Marder, From Dreadnought to Scapa Flow, 117.

[9] Marder, From Dreadnought to Scapa Flow, 116.

[10] Gretton, “The U-boat Campaign in Two World Wars,” 134.

[11] Gretton, “The U-boat Campaign in Two World Wars,” 134.

[12] Carl Boyd and Akihiko Yoshida, The Japanese Submarine Force and World War II, (Annapolis, MD: Naval Institute Press, 1995) 5.

[13] H.P. Willmott, Empires in Balance: Japanese and Allied Pacific Strategies to April 1942, (Annapolis, MD: Naval Institute Press, 1982) 88.

[14] Willmott, Empires in Balance, 88.

[15] Mark P. Parillo, The Japanese Merchant Marine in World War II, (Annapolis, MD: Naval Institute Press, 1993) Table A.9, 243.

[16] Parillo, The Japanese Merchant Marine in World War II, Table A.9, 243.

[17] Parillo, The Japanese Merchant Marine in World War II, 207.

[18] Parillo, The Japanese Merchant Marine in World War II, Table A.9, 243.

[19] Holger Herwig, ‘Luxury’ Fleet: The Imperial German Navy 1888-1918, (London: Allen and Unwin, 1980) 38.

[20] Marder, From Dreadnought to Scapa Flow, 122.

[21] Marder, From Dreadnought to Scapa Flow, 125-126.

[22] Marder, From Dreadnought to Scapa Flow, 125-126.

[23] Gretton, “The U-boat Campaign in Two World Wars,” 134. 

[24] Samuel Elliot Morison, Strategy and Compromise, (Little, Brown, and Co., 1958) 73.

[25] Parillo, The Japanese Merchant Marine in World War II, 10.

[26] Parillo, The Japanese Merchant Marine in World War II, 152-153.

[27] Parillo, The Japanese Merchant Marine in World War II, 16.

[28] Parillo, The Japanese merchant Marine in World War II, 16.

[29] Willmott, Empires in the Balance, 88.

[30] Willmott, Empires in the Balance, 82-84.

[31] Willmott, Empires in the Balance, 82.

[32] Marder, From Dreadnought to Scapa Flow, 120-121.

[33] John Slessor, “Admiralty Command Policy in Two World Wars: Reflections Based on Arthur Marders’ Story of Jutland,” in Naval Warfare in the Twentieth Century, ed. by Gerald Jordan, (London: Croom Helm, 1997)124.

[34] Gretton, “The U-boat Campaign in Two World Wars,” 134

[35] Gartner, “Strategic Assessment in War,” 78.

[36] Marder, From Dreadnought to Scapa Flow, 159.

[37] Marder, From Dreadnought to Scapa Flow, 161.

[38] Marder, From Dreadnought to Scapa Flow, 160.

[39] Marder, From Dreadnought to Scapa Flow, 159.

[40] Gretton, “The U-boat Campaign in Two World Wars,” 133.

[41] Marder, From Dreadnought to Scapa Flow, 150.

[42] Marder, From Dreadnought to Scapa Flow, 150.

[43] Marder, From Dreadnought to Scapa Flow, 154-155.

[44] Parillo, The Japanese Merchant Marine in World War II, 22.

[45] Parillo, The Japanese Merchant Marine in World War II, 22-23.

[46] Parillo, The Japanese Merchant Marine in World War II, 22-23.

[47] Parillo, The Japanese Merchant Marine in World War II, 24-25.

[48] Parillo, The Japanese Merchant Marine in World War II, 24-25.

[49] Willmott, Empires in the Balance, 82; Parillo, The Japanese Merchant Marine in World War II, 19.

[50] Parillo, The Japanese Merchant Marine in World War II, 23.

[51] Joel Holwitt, “Unrestricted Submarine Victory: The U.S. Submarine Campaign Against Japan,” in Commerce Raiding: Historical Case Studies, 1755-2009, ed. by Bruce A. Elleman and S.C.M. Paine, (Newport, Rhode Island: Naval War College Press, Center for Naval Warfare Studies, 2013) 233.

[52] Joel Holwitt, “Unrestricted Submarine Victory: The U.S. Submarine Campaign Against Japan,” 233.

[53] Joel Holwitt, “Unrestricted Submarine Victory: The U.S. Submarine Campaign Against Japan,” 234.

[54] Parillo, The Japanese Merchant Marine in World War II, 218-219.