Naval War College Review Volume 66 Article 6 Number 2 Spring 2013 The C“ onsequent Interest” of Japan’s Southwestern Islands: A Mahanian Appraisal of the Ryukyu Archipelago Eric Sayers Follow this and additional works at: https://digital-commons.usnwc.edu/nwc-review Recommended Citation Sayers, Eric (2013) "The C“ onsequent Interest” of Japan’s Southwestern Islands: A Mahanian Appraisal of the Ryukyu Archipelago," Naval War College Review: Vol. 66 : No. 2 , Article 6. Available at: https://digital-commons.usnwc.edu/nwc-review/vol66/iss2/6 This Article is brought to you for free and open access by the Journals at U.S. Naval War College Digital Commons. It has been accepted for inclusion in Naval War College Review by an authorized editor of U.S. Naval War College Digital Commons. For more information, please contact [email protected]. Sayers: The “Consequent Interest” of Japan’s Southwestern Islands: A Mah THe “CONSEQUENT INTEREST” oF JAPAN’S SOUTHWESTERN ISLANDS A Mahanian Appraisal of the Ryukyu Archipelago Eric Sayers n his classic collection of essays on maritime geography The Interest of America in Sea Power, Present and Future, Alfred Thayer Mahan opined that the importance Iof “portions of the earth’s surface, and their consequent interest to mankind, dif- fer from time to time.”1 Just as the Mediterranean Sea once transfixed the minds of European strategists and policy makers, Mahan believed, at the turn of the twentieth century, the Gulf of Mexico and Caribbean Sea would obtain similar prominence in American strategic thinking. A century later, as we observe the relative balance of economic and military powers shifting to Asia and the Pacific and Indian Oceans, Mahan’s teachings on geography are again instructive, as once seemingly insignificant bodies of water and island chains take on a new importance in regional security matters. Recent research has drawn attention to the interaction of commercial and martial activity in the Indian Ocean, Malacca Strait, and South China Sea.2 To this group of portentous maritime zones should be added Japan’s southwestern island chain—and specifically the Ryukyu Islands in the East China Sea.3 The ongoing territorial dispute between the People’s Republic of China (PRC), Japan, and Taiwan over the Senkaku/Diaoyu island group Mr. Sayers is Defense Policy Advisor to a U.S. con- near the southern end of the Ryukyu chain; the gressman on the House Armed Services Committee. southwestern islands’ geographic proximity to the He conducted the research for this publication as an People’s Republic of China and Taiwan; and the SPF resident fellow at the Pacific Forum CSIS. Mr. Sayers earned a master of science degree in strategic former’s expanding naval capabilities and ambi- studies at the S. Rajaratnam School of International tions promise to ensure, as Mahan’s adage con- Studies in Singapore. tends, the Ryukyus’ “consequent interest” to Japan 4 Naval War College Review, Spring 2013, Vol. 66, No. 2 and its neighboring states. Published by U.S. Naval War College Digital Commons, 2013 1 6267_Sayers.indd 45 2/26/13 8:44 AM 46 NAVAL WAR coLLEGENaval RE WarVIEW College Review, Vol. 66 [2013], No. 2, Art. 6 After hugging its own shores for decades, since 2004 the PRC’s People’s Lib- eration Army (PLA) Navy has increased its activity around Japan’s southwestern islands. In what appeared as a response to this more assertive posture of the PLA Navy (or PLAN) the Japanese Ministry of Defense in its 2010 National Defense Program Guidelines (NDPG) identified the southwestern islands as a priority for defense spending and advocated a shift in the nation’s strategic focus to them. Why has China taken an interest in these islands and their surrounding waters? What explains Japan’s new strategic emphasis on its southwestern islands? What form will Japan’s strategy take in response to China’s increased focus on them and activity there? This article seeks to explain the growing strategic importance of Japan’s southwestern island chain and to understand how Japan is responding to China’s increased maritime activity in this zone. The article has five sections. The first two review the geography of the southwestern islands and evaluate the strategic importance of these islands by adopting a topology that Alfred Thayer Mahan developed to assess a geographic location’s strategic value. The third section evaluates China’s maritime interests in the Ryukyus and reviews the PLA’s capa- bilities and war-fighting missions that affect the islands. The fourth describes the Japanese government’s strategic focus on the southwestern islands as articulated in the 2010 NDPG. The final section draws conclusions on Tokyo’s likely course of action in this area. JAPAN’S SOUTHWEST, OR “RYUKYU,” ISLANDS The history of Japan’s southwestern islands stretches back to the establishment of the Ryukyu Kingdom in 1429. From the fifteenth to the nineteenth centuries the kingdom embraced all of the island chain, from the Amami Islands below Kyu- shu in the north to the Sakishima Islands near Taiwan in the south. During this period, the kingdom paid tribute to both the Japanese shogun and the Chinese emperor. In 1609 the Japanese feudal domain of Satsuma invaded the Ryukyu Kingdom and took control of it after a swift victory. In 1853, on his way to open trade relations with Tokyo, Commodore Matthew Perry transited the Ryukyus, stopping over at Naha. Less than two decades later, in 1872, the Japanese Meiji government abolished the kingdom, declaring it the Prefecture of Okinawa in 1879. Following World War II, the U.S. government maintained administrative rights over the islands, while recognizing Japan’s residual sovereignty. Full sover- eignty over the islands was ultimately returned to Japan in 1972. Japan’s southwestern islands form a seven-hundred-mile-long chain that flanks the coast of China, from the Japanese home island of Kyushu to near the northeast coast of Taiwan. In Japanese, the overall chain is known as the Nansei- shotō (Nansei Islands). The Satsunan Islands make up the northern half of the https://digital-commons.usnwc.edu/nwc-review/vol66/iss2/6 2 6267_Sayers.indd 46 2/26/13 8:44 AM Sayers: The “Consequent Interest” of Japan’s Southwestern Islands: A Mah SAYers 47 N ansei Islands and the Ryukyu Islands, including the Okinawa Islands and the Sakishima Islands, the southern half. This article will focus on the Ryukyus, including Okinawa and the larger islands of Miyako, Ishigaki, Iriomote, and Yonaguni. The Okinawa Islands form the northern portion of the Ryukyus, almost four hundred miles south of Kyushu. Okinawa itself is the largest in the Ryukyu chain, stretching sixty miles from the northeast to the southwest and ranging from two to sixteen miles wide. The northern portion of the island, known as Kunigami, contains a dense mountain ridge with streams and valleys where water is abun- dant. The midsection, known as Nakagami, is marked by limestone ridges and rolling hills; below that is a hilly southern area called Shimajiri. The majority of Okinawa’s population of almost 1.4 million people lives in the urban areas of the south. The major islets of the Okinawa group are scattered to the north and west, including Yoron, Iheya, Izena, Zamami, and Tokashiki. Naha’s harbor and airport are located in the southwestern portion of the island and serve as major transit points to the rest of the Ryukyus. While one’s typical mental map of Japan is challenged to visualize the archi- pelago as stretching southward beyond Okinawa, in fact the twenty islands that make up the Sakishima portion of the Ryukyus pepper the waters of the East China Sea for roughly three hundred nautical miles, from Okinawa all the way to within a hundred miles of the coast of Taiwan. Governed as part of Okinawa Prefecture, the Sakishimas include the contested Senkaku/Diaoyu Islands and the main islands of Miyako, Ishigaki, Iriomote, and Yonaguni. The Miyako chain, with its main island of Miyako, is the first group of the Sakishimas south of Okinawa. The Miyako Strait separates Miyako Island from Okinawa by roughly 145 nautical miles and runs 500–1,500 meters deep. The triangle-shaped island is composed largely of limestone formed by the raised coral, with a maximum height of 378 feet. Because it is relatively flat, it is densely settled (a population of roughly fifty thousand) and intensely cultivated. Large limestone ridges run north and south along the island’s coast. Miyako is flanked by a number of even tinier islands, including Kurima, Shimoji, Irabu, and Ikema. Both Kurima and Ikema are accessible from Miyako by bridge. Miyako’s Hirara civilian port is on the northwest portion of the island facing Irabu. Farther south lies the Yaeyama Island chain, including the major islands of Ishigaki and Irio- mote and the westernmost island of the Ryukyus, Yonaguni. The Ishigaki Strait, separating Ishigaki from Miyako, is twenty-five nautical miles wide and from seventy to five hundred meters deep. It is sliced in half by the islands of Tarama and Minna. Ishigaki Island is eleven miles long and consists of a southern plain and a northern mountainous spur. A low beach extends along the southern coast, where the Ishigaki port is located. The island’s total population is roughly forty Published by U.S. Naval War College Digital Commons, 2013 3 6267_Sayers.indd 47 2/26/13 8:44 AM 48 NAVAL WAR COLLEGENaval REVIEW War College Review, Vol. 66 [2013], No. 2, Art. 6 RYUKYU ISLANDS Okinawa Yonaguni Miyako Ishigaki Tarama Iriomote MIYAKO (TOP) AND YONAGUNI (BOTTOM) ISLANDS Shimoji Airport JASDF Radar Station Miyako Airport © 2012 Google, ZENRIN Yonaguni Airport Port © 2012 Google, ZENRIN https://digital-commons.usnwc.edu/nwc-review/vol66/iss2/6 4 6267_Sayers.indd 48 2/26/13 8:44 AM Sayers: The “Consequent Interest” of Japan’s Southwestern Islands: A Mah SAYers 49 thousand.