To Be or Not to Be: Japan’s Reliance on Mahan’s Strategy during World War II Geographically, Japan is an island nation that is slightly smaller than the state of California, with an area of 377,915 square kilometers. However, Japan has a coastline that is almost 30,000 kilometers in length in comparison to the United States coastline, which is 19,924 kilometers in length. It is narrowly separated from modern-day Russia, North Korea, South Korea, and China by the Sea of Japan and the East China Sea. On maps the largest cities in Japan are on the Eastern side of the island chain, looking toward the Atlantic Ocean, and it boasts few natural resources, besides fishing. The geography of Japan and its proximity to its neighbors has shaped the strategic policy of Japan for centuries, and has driven the necessity of a strong navel strategy. However, it did not always have naval aims. During World War II, while Japan strongly relied on the writings on Alfred Thayer Mahan (1840-1914) in developing their national and naval strategy. However, their strategy had some fatal flaws that would prevent a victory or a negotiated settlement with the United States. Mahan is often compared to the highly esteemed Jomini and Clausewitz, who were famous for their land-based military strategy. However, many of his ideas were not new; they were derived from historical sources from which he distilled and clarified some major concepts. Mahan’s huge contribution to Navel strategy was the organization and the forceful presentations of those ideas. His influence on navy strategy was especially strong in Japan, where by 1907, Mahan felt that his works had been more translated than in any other language. In fact, he was so respected in Japan that in 1902 he was offered a teaching position at the Japanese Naval Staff College by Admiral Yamamoto Gombei. His best-known work is called, “The Influence of Sea Power upon History (1660-1783), and was published in 1890. This book contained three essential elements that contributed greatly to ideas of navel expansion: Sea Power, Naval Power, and Navel strategy. Sea Power is much different than Naval power in that it includes not only the strength of the Navy, but also everything associated with commerce and shipping, including bases to protect that shipping. An increase in colonies, trade, and shipping would require a larger Navy to protect those assets, and bases to protect those assets. This trade and shipping would also generate revenue to support a large Navy. The following 6 factors are what Mahan says affect a country’s sea power: geographical position, physical conformation, extent of territory, population size, character of the people, and character of the government.
Geographically, the location of Japan is favorable for the development of sea power because it is a link between east and west trade routes. Physically, the land mass is small, with few natural resources other than fishing. Since the land is small and scattered, there is little need for a large army to protect the land, so resources could be focused on the Navy. In addition, prior to World War II there were approximately 80 million people living on four Japanese islands, so there was a large population that was experienced in marine construction, fishing, and other nautical related enterprises. So, Japan has the first four factors to make a great sea power.
The character of national government and that of the people of Japan was not what Mahan described as contributing to sea power prior to World War II. The government was not really interested in developing a strategy based on their Navy. Normally, strategy is defined by the leader; however, the only leader in Japan at the time was Emperor Meiji. The civil government was almost entirely separate from the military and was largely ineffective because of the need to achieve consensus when taking problems or issues in front of the emperor. If an advisor to the emperor was wrong, they were honor bound to commit suicide, but not if it was a consensus. However, if consensus was not achieved, the government often deadlocked and they were over-ridden by the Army and Navy. The Army and Navy were in competition for resources. On the domestic side, there was a lot of government corruption, rural poverty, and starvation, so expansion to the Asian mainland was viewed as a solution to some of these problems. This had the enthusiastic support of the Army. In addition, permeating Japanese society, there was a strong sentiment or belief in 1940 of hakko ichiu, or that it is the fate of the Japanese to rule all of Asia. As a result, people and the government were focused on an army strategy to solve some of their economic worries, not a Navy strategy; however, Mahan’s book gat the Navy the justification for shifting the focus and the resources back on the Navy. Keep in mind that Mahan did not believe that a nation could be both a great land and a great sea power, and that certain factions in Japan wanted to be both.
Central to Mahan’s teachings on strategy is the key concept of command of the sea, which means that if control of the sea is desired, the enemy’s ships are the focal point or concentration of resources and firepower. Firepower to Mahan was found in the battleship, and the best way to defend the country is to wage an offence against the enemy and to have a decisive battle. The Japanese and the US seem to have bought into this philosophy. However, with innovation and improvements in Navel aviation, the importance shifted from the battleship to the carriers. The carriers had the advantage of being able to scout with planes, and to provide some cover during engagements. So, the battles could be fought with the two opponents out of sight of one another, which is very different than historical naval battles that Mahan had studied. When Pearl Harbor was bombed on December 7, 1941, Japan had the largest carrier force and some on the most experienced naval aviators that the world had ever seen. However, during the war Japan was only able to develop for additional fleet carriers, while the US managed to build 17 because of their larger amounts of resources. Unfortunately the Japanese Navy had a philosophy that, “Fighting spirit was everything and material resources were nothing,” which would lead them to some strategic mistakes in the war. Mahan would certainly disagree with this philosophy because of his linking of sea power, naval power, and commerce and material goods. Commerce and material goods support the other two, and they then support and protect commerce.
By 1940, the US was quietly preparing for the possibility of war with Germany, so they increasingly needed raw materials. Japan was very successful in their war with China, but the US was not supportive of Japan’s aggression. Northern Indochina was strategically important to Japan, because they believed that supplies from the US and other allies were aiding the Chiang Kai-shek government. Japan wanted to shut the supplies down, so they invaded Northern Indochina. In addition, Japan signed an alliance, the Tripartite Pact, with Germany and Italy in September of 1940. Prior to this, the Export Control Act of July 2, 1940 authorized the President, in the interest of national defense, to prohibit or curtail the export of basic war materials. By the winter of 1940-1941, we cut off most strategic commodities to Japan that included: Arms, ammunition, aviation gasoline, other petroleum products, machine tools, scrap iron, pig iron, iron and steel manufactures, copper, lead, zinc, and aluminum. Oil was not included in this list because the US feared that cutting off oil to Japan would cause them to strike south, to Indonesia and other locations. However, with the fall of most of France to Hitler, Japan saw an opportunity to help them in their conquest of French Indochina (parts of Vietnam and Cambodia). Given an ultimatum to surrender, the government of Indochina agreed to allow Japan to have a joint protectorate over that country. During this time the Roosevelt administration intercepted a telegram, and from that telegram they believed, incorrectly, that Japan was going to invade the Dutch East Indies. As a direct result, on July 26, 1941 the US imposed an oil embargo on Japan, and Roosevelt signed an executive order freezing Japanese assets within the US. Japan got approximately 80% of its oil imports from the US, so this was a severe blow to their war effort. When this embargo took effect in August of 1941, the Japanese Navy made an assessment on their supplies, which indicated that their supply would be depleted by the second year of the war. This allowed the Japanese Navy to sway army opinion towards securing oil supplies from Indonesia, and towards striking the US during the initial hostilities, instead of waiting till after oil supplies from Indonesia were secured.
One of the major elements of Mahan’s strategy was largely ignored by the Japanese when drawing up war plans, and that was lines of communication. According to Mahan, “Communications dominate war; broadly considered, they are the most important single element in strategy, political or military…The Sea therefore, is the great medium of communication—of commerce.” The Japanese, based on force strength knew that they could only hold their own for the initial phase of a war with the US. However, because they were so focused on developing and building carriers for a decisive victory, they neglected securing communication. All economic, personnel, and material resources had to be directed to building and maintaining the combined fleet. Convoy escorts were not built in large numbers. These are ships that served as escorts to ensure that a convoy of ships were not scattered, captured or destroyed. The carrier escorts were to be built or assembled when war was declared, but there were too few to ensure communications when it came. This caused heavy casualties to Japan throughout the war. In addition, Mahan advocated bases, but not too many bases on land to support the lines of communication and the fleet. The US was able to take these bases one by one because of not securing lines of communication.
Once Japan’s national strategy was determined that they were to eliminate the American threat and to seize British and Dutch holdings in the South Seas, the military began to devise their military strategy to achieve these national goals. When they started this process, they clearly stated that they needed to have the maximum concentration of force, which is a very Mahan like strategy. However, there were disagreements about where to strike first, to go south and seize oil in the South Seas or to strike the American fleet, concentrated at Pearl Harbor. The logic behind striking Pearl Harbor first was to deal with the enemy first, so that the US could not interfere with operations in the South Sea. So, they would crush the US at the outset in a decisive victory, which is another Mahan idea. The final plan for the military was called “Centrifugal Offensive”, which called for striking Pearl Harbor with six large fleet carriers while simultaneously driving into the South Sea on two fronts. Yamamoto insisted that only the best commanders were used for leading the operation—another Mahan position. Once their objectives were secured, they would consolidate their holdings, create a defensive perimeter, and seek a negotiated settlement with the US.
The Centrifugal Offensive plan was successful, but it did begin to deviate from Mahan in that the forces of the Japanese were actually dispersed and not concentrated. In addition to Pearl Harbor, the Japanese planned to advance to the south on two fronts. The first front would strike Malaya, and then go on to Sumatra and western Java, and also some strategic locations in Borneo. The second front would strike the Philippines and advanced through Makassar Strait to eastern Java. It was successful and completed when Java surrendered on March 8, 1942, with a minimum of casualties for the Japanese. However, some of the dispersion of force was not necessary. The US presence in the Philippines was not really a threat to the southward movement of Japan, and it could not seriously disrupt the lines of communication. Even though US airpower presence in the Philippines was the largest outside the US, there were still only a total of 193 planes in the country. In addition, the ships in that were located there could not seriously challenge the imperial fleet. The success of the Centrifugal Offensive was perceived as Japanese superiority, so the Japanese did not follow their original plan to consolidate their holdings, and secure their lines of communication. Instead, they went looking for further conquests, which would overextend their resources.
Strategically, the Pear Harbor attack was foolish, and at the operational and tactical level it did not successfully destroy the US fleet and our capability to rapidly rebuild our forces to challenge Japan. Overall, the Japanese knew that they could not sustain a prolonged war with the US because they did not have the US industrial resources and capabilities. They wanted a limited war with the US and believed that we would tire of the war and negotiate with them. However, they started the war with no clear idea of how to exit the conflict and fight only a limited war. In addition, they knew that the US fleet in Hawaii could not and was not prepared to stop a rapid advance into South Sea. Troops would have to be ferried from the mainland to bring the crews located on Pearl Harbor to full strength, which would take time. What they did not know was if the US would attack because of their aggression into the South Sea to capture Java, especially if the interests of the US were not threatened. The US was strongly isolationist at this time period, and had not responded strongly to other provocations. On the tactical and operational side, the focus of the attack was misplaced on the battleships and aircraft. While taking battleship row out was important, they did not destroy the carrier task force, did not destroy the fuel depots, and they left the dry docks and other maintenance facilities untouched. The overall commander of the six Japanese carriers decided to come home rather than risk losses by looking for the American carriers. This was not a Mahan blow to the US because it did not cripple the ability to wage war, nor did it prevent the US from recovering quickly to rebuild its strength.
In many ways, the Japanese underestimated the US in their resources, strength, and willingness to wage war. Japan wanted a limited war with the US, and were only thinking about their existence and their defense, they did not envision how the war could or would end. By striking Pearl Harbor and starting the war in the Pacific, they launched a total war, where it would be determined not only by military and strategic factors, but also by economic, technological, political, diplomatic, and ideological factors. This was a war where the Japanese would and could be worn down through attrition by superior economic power, and by decisive battles in the Pacific.
There is a day, a day in infamy that will never be forgotten, and that day is December 7, 1941. On this day Japan attacked the United States at Pearl Harbor. This day is not only an important day to remember and reflect in the US, but also a time for Japan. In so many instances the war in the Pacific might have been different had the government of Japan focused more on diplomacy and less on imperialism. While Japan’s strategy and tactics were based on Mahan’s writings and strategic advice, it doesn’t quite fit. Japanese strategy was focused much of the time on operations and tactics, because of their combat experience. They pulled most of their strategy from their recent past in wars with Russia and on the continent, while fitting Mahan’s writings into those experiences, and pulling Mahan’s concepts to justify the Navy’s need for funding from the government. While Japan respected and used Mahan’s writings, he was not the father of Japanese Strategy in World War II.

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