Recently the Samurai Archives devoted a few episodes of their podcast to dissecting the relationship between military history and Japanese studies. The lead discussant on the program is Nathan Ledbetter, who blogs once a year or so at Sengoku Field Manual but comments regularly at the Samurai Archives forums. In these episodes his focus is on Anglophone scholarship, and he traces attitudes towards Japanese political and military history among Anglophone scholars from the days of George Bailey Sansom to the present. The episodes are interesting, and I suggest you take the time to listen to them. Many of their themes mirror what I have written about the historiography of Chinese military history. Indeed, the historiography of the two subjects match each other well enough to to justify analyzing both under a broader term like "East Asian military history."  In that vein, there are a few points I would add to Ledbetter's analysis:
On the decline of military history generally: Ledbeter starts his discussion by describing the fortunes of academic military history in general. Military historians are few and far between in today's academy, and Ledbetter pegs this as a consequence of the Vietnam War. As he tells it, opposition to that war led to distaste for all wars, which in turn led to disdain for the formal study of any of them. This account is true but incomplete. A narrow focus on military history may mislead us here, for the changes that overtook academia in the late '60s and early '70s were in fact much broader than one sub-discipline, or indeed the discipline of history as a whole. The Vietnam war was a part of this, but so too was the Civil Rights Movement, the dismantling of Europe's colonial empires, the May 1968 strikes, the Watergate Scandal, and the complete collapse of institutional Christianity in Western Europe. These events changed the way Westerners thought about their world, empowering voices once ignored and discrediting traditional authorities across the board. Power was no longer in vogue. For historians this meant casting aside narratives that took the perspective of the powerful–and out went the sub-disciplines that which specialized in telling stories from this perspective. Military history was one of these sub-disciplines, but it was not the only one. Political history, diplomatic history, intellectual history, and economic or business history also took a hit. Indeed, these other sub-disciplines fared much worse than military history, in proportional terms. 
|Fig. 1 and 2 from Robert Townsend, "The Rise and Decline of History Specializations over the Last 40 Years," |
Perspectives on History (December 2015).
Military historians survived this upheaval by weaving their narratives out of a new sort of warp and weft. Most importantly, historians began to tell the story of warfare from perspectives rarely explored in earlier eras. This is where the "War and Society" version of military history started, as historians sought to highlight voices missing from the old bugle-and-battles narratives. Some of these new histories told stories that would not traditionally have been considered military history at all–how a war was experienced by its widows, for example, or how the imagery or poetry and art of a society at war changed as death tolls mounted. But more traditional campaign narratives also began to change. Traditionally, these narratives often took the perspective of commanders and generals; the battle maps marked with x's and arrows you find in U.S. Civil War atlases are products of this sort of thinking. In the '70s and '80s this focus began to shift. John Keegan's Face of Battle and Paul Kennedy's Rise and Fall of Great Powers are two landmark examples of the discipline's new priorities. Keegan's book posed questions like, "what compelled soldiers on the front line to fight in different eras of history?" and "what did it feel like to be a grunt at Agincourt, Waterloo, or the Somme?" While he was not the first to attempt these questions, he was one of the best prose writers to do so, and his book caught the attention of professional historians and laymen alike. As such Face of Battle was one of the most important works of military history written during the 20th century; after it was published no historian could get away with writing a narrative history of any war without describing what it looked like on the ground.
If Keegan telescoped in on the individual soldier, Kennedy's Rise and Fall expanded the narrative out until it included the workings of entire nations and economies. Kennedy suggested that success in battle had much less to do with operational art or strategic savvy than economic growth and industrial policy. For him victory in war was decided first and foremost by macroeconomics. Kennedy's presentation thus inverted the concerns of the War and Society researchers. Where they focused on how waging war changed a nation's social life, Kennedy asked how a country's social life changed the way it waged war. A number of works in a field that would be later called "world history" anticipated Kennedy's quest to tie the history of military conquest to globe-spanning macrohistorical trends, but only a few of these were ever received with the enthusiasm that showered Kennedy's Rise and Fall. That has changed. Today one or two books of this type are published every month.
The popularity of Kennedy and Keegan's books with "general readers" suggests that there was more to military history's new direction than the whims of academic fashion. There was real demand for works that presented warfare and strategy from new perspectives. While a few historians--here John Lynn comes to mind--have tried to revive the more traditional sorts of narrative campaign histories, most felt that this new style of military history was a necessary corrective to what came before.  The story of generals and statesmen had been told many times over the centuries; the stories of the soldiers, and of the societies transformed by soldiering, had yet to be told. For the past three decades Western military historians have busied themselves telling these stories.
This brings us to my second point. Contemporary historians of East Asia have the same basic set of priorities as the rest of their profession. They focus on structures, cultures, identities, and the hidden voices of history. This is unfortunate, for the historiography of East Asia--especially premodern East Asia--did not follow the same path of development as the historiography of Europe and North America did. The flight from narrative campaign histories was an understandable reaction to high politic's dominance in the literature. However, in the study of East Asian history, narrative political, diplomatic, and military histories never dominated to begin with. The idea that East Asianists need to counter the biases of existing, politics-heavy narratives is mistaken, for in too many cases there are no existing narratives to counter in the first place.  We are left with huge gaps in the literature. In the case of military history, there are entire wars where millions of people fought and died, and whose stories are instantly recognized by people across China, Japan, and Korea today, that still have no books written about them in English.
Part of the problem is size. The number of East Asianists in academia is small. The number working on pre-modern East Asian history is pitifully small. You can count the number of American scholars who specialize in Silla Korea on one hand. You could count those who specialize in Sengoku Japan on two. You could fit all the specialists on the Northern Song Dynasty on a moderately sized tour bus. This is true now; back when narrative political and military histories was more academically fashionable (c. 1920-1960) the number of East Asianists were even smaller. Because only a few scholars specialized in East Asia then, the peculiar research interests of one scholar and his pupils forty years ago have come to dominate entire fields today (one example of this is the substantial amount of work done on medieval Japan's institutional history, something I credit entirely to the influence of John Whitney Hall, who taught Japanese history at Yale for the better part of the last century). There simply weren't enough historians writing then to fill in the gaps.
In addition, many of those who wrote then were relatively unconcerned with high politics, diplomacy, or military affairs. They came to the study of traditional Asia with a set of non-traditional backgrounds. Then—as now—a great deal of East Asian history is written by philosophers, philologists, and archaeologists. These are men and women who began to study East Asia because of a fascination with Pure Land Buddhism, Neoconfucian metaphysics, Shang Dynasty bronzes, or reconstructing classical Chinese pronunciation. In most areas linguistics, philosophy, literature, and religious studies are separate fields, but in the case of the East Asianists (and here a fruitful analogy with the Classicists can be made) they blur somewhat. The very term "East Asianist" (along with its subsets: "Sinologist,""Koreanist," etc.) express the expectation that those studying one aspect of pre-modern Asia should be conversant in all of its other domains. In this milieu intellectual history has always been king. This is partially because many of these disciplines began as an attempt to make the "Eastern mind" accessible to Westerners, and it is partially because it is incredibly difficult to understand even fairly mundane historical sources without a working knowledge of classical Chinese and the history of ideas in East Asia.  The interdisciplinary nature of this sort of intellectual history sheltered it somewhat from the political storms and of the '60s and '70s. It is still the strongest strain of historical scholarship on the region.
The downstream effects of all this are pretty easy to see. By far the most common textbook for introductory survey courses of East Asian history is Sources of the East Asian Tradition, a collection of mostly philosophical and literary documents from the last few thousand years of East Asian history. The Association for Asian Studies annual conference rarely has panels on the political or military history of Sengoku Japan, but there will always be room for one more panel on the Tale of Genji to be squeezed in.
Most important of all, however, is a limited sense of audience on the part of the East Asianists. I hammered this point home in my "Chinese Strategic Tradition: A Research Program" essays, so I'll be a bit briefer here. In essence, East Asianists are prone to write for each other. Only each other. This is partly because a lot of the legwork of East Asian history involves debating esoteric items like the details of a calendar system no one has used for a thousand years or reconstructing the pronunciation of 9th century Vietnamese and 17th century Manchu. It is also because popular interest in East Asia is really quite a new thing. But it is a thing. This is something few East Asianists realize. About a year ago I had an experience that brought this lack of vision to my attention in a rather forceful way. I was exchanging messages with a grad student who was then in the beginning stages of a dissertation on the early Song dynasty. I asked him if he would ever be interested in writing a narrative account of the political and military events that occurred during the period in question. He asked in response: "Why would I ever want to do that? That would just be rehashing the Zizhi Tongjian. What would be the point?" This is an extraordinary statement. The Zizhi Tongjian is a 20 volume history written in the 1070s AD. It is regarded as one of the greatest historical works of East Asia. It also has not been translated into English! You could fit all of the Westerners fluent enough in classical Chinese to read the Tongjian in a small auditorium. Sharing the information contained inside the Tongjian with the millions who don't read classical Chinese would be a worthy deed. There are scholars who study political science, strategic studies, and world history who would be eager to read a narrative account of the period. If it was written well enough it might catch the interests of thousands of 'educated readers' outside the academy altogether. But it is not to be! The only audience that mattered to my interlocutor was the one who could read the Tongjian already.
Wang Wensheng made a similar critique in his book on the White Lotus Rebellion: "Most historians and social scientists tend to focus more on the explanatory power of structures while remaining less informed about the significance of events."  Wang sees this as problem ailing all historians, but it is clear to me that it afflicts some sub-disciplines more than others. Were you to pick up the five or so most cited books on Europe during the Thirty Years War or England and France during the Hundred Years War you would leave with a firm chronology of the main events of each. But in East Asian historiography there are some eras—for example, Sengoku Japan—which an extensive amount has been written about, but which still fail to provide the reader with any narrative account of what actually happened. In the case of Sengoku Japan, there are (thanks to John Hall's students) a great number of studies on the institutional history of late Medieval Japan. Many scholars have investigated how the relentless warfare of that era shaped the country's political and religious institutions, transformed its culture and arts, and altered its social structure. You can learn without much difficulty how Sengoku Daimyo funded their conquests, fed their troops, managed their inheritance, dealt with the Buddhist monastics and Christian missionaries roaming the country, distributed booty, passed laws, negotiated with the court, regulated industry and farming, selected generals, and thought about political and military authority in general. But if you want to discover the story of individual Daimyo or individual Daimyo domains, then there is little you can find in a book store to help you. Historians of Japan write with the assumption that the reader of his or her works is already familiar with the major events and players of the time period—and for the most part they are right, for no one but other specialists in Medieval Japan can read that sort of scholarship.
There is something of a self fulfilling prophecy at play here. I don't expect it to end any time soon. There is a strong demand for histories of East Asia's many wars. This demand is unmet. Until East Asianists deem readable narrative accounts as more than redundancies unworthy of their time, this will always be the case.
"The Chinese Strategic Tradition: A Research Program, Part I" and Part II
-A more formal and in depth review essay on Chinese military history and strategic theory.
"Darwin and War in Ancient China, Sengoku Japan, and Early Modern Europe"
-Why I read all those institutional histories of Sengoku Japan in the first place.
"The Road to Beijing Runs Through Tokyo"
-In which I argue that a cadre of Japan experts is a more critical national security need than a cadre of China hands.
 This attitude is not simply a relic of the '60s. See Adam Elkus's recent (9 Dec) post on those who attack scholars studying terrorism for producing 'actionable' insights.
Also, the numbers in the graphs can be a bit deceptive. See John Lynn's article in note 3 for an explanation of why military history is in rather dire straights at the institutional level.
 John Lynn, "Breaching the Walls of Academe: The Purposes, Problems, and Prospects of Military History," Academic Questions 28, iss 1 (2008), pp. 18-36; “The Embattled Future of Academic Military History,” Journal of Military History 61, no. 4 (October 1997), pp. 777-89.
 An exchange I had about Muromachi era with one professor is a fairly typical example. He told me how much he loved Pieree Souryis' The World Turned Upside Down: Medieval Japanese Society (Asia Perspectives: History, Society, and Culture) because it focused so much on the organizational efforts of peasants and Buddhist orders instead of just focusing on the samurai. "The problem with a lot of Japanese history is that historians are to apt to sympathize with the Samurai and tell the story from their perspective. Books like this show something different."
I concede that Souryi's book is fascinating, and probably the single best introduction to medieval Japan to boot. However, his notion that the majority of books are written from the perspective of the Samurai is absolutely false, especially if it is the Muromachi era up for discussion. This may be true in Japanese, but it is not true in English. Daimyo like Takeda Shingen and Uesugi Kenshin, who are household names in Japan, have no biographies in English. You will be hard pressed to find any book that tells their story even in a cursory fashion. And these are two of the most famous men in Japanese history! Were one to tally all the books published about Muromachi/Sengoku Japan up I suspect that you would find more about the beliefs, practices, and organization of Japan's monastic orders (or the culturally elite but politically marginal aristocrats in Kyoto) than you would about the Daimyo.
 This is true for Western historical sources as well, of course, but it is less apparent to us because we are taught the basic ideas and references from a young age.
 Wang Wensheng, White Lotus Rebels and South China Pirates: Crisis and Reform in the Qing Empire (Cambridge: Harvard University Press, 2014), p. 10.