Study at TCU


Name MARUSHIMA Kazuhiro
Official Title Associate Professor
Affiliation Faculty of Liberal Arts and Sciences(Department of Humanities and Social Sciences)
Profile  My specialty is medieval Japanese history, especially studying Sengoku daimyo. I do not think of the Sengoku daimyo as a tyranny, but as a power supported by his vassals. Therefore, I attach great importance to the study of vassals. The territory of the Sengoku daimyo is dotted with the territories of the miniature Sengoku daimyo called "Kunishu" who have been granted autonomy. Since the political trends of "Kunishu" have a great influence on the policy of the Sengoku daimyo, research on "Kunishu" is also a big issue.
 So far, the main research materials have been the Takeda clan and other eastern Japanese daimyo such as Hojo, Imagawa, and Uesugi. Currently, we are considering the Daimyo of Kyushu and "Kunishu", specifically the Shimazu, Sagara, and Arima clan. As a result, we are proceeding with comparative research with the daimyo of eastern Japan. From a long-term perspective, it is also a process of expanding to the Oda administration theory and Toyotomi administration theory.
 The basis of my research is Diplomatics(Historical materials). However, there is little research on ancient writing in the Warring States period. Systematizing this is another issue.
Research Field(Keyword & Summary)
  1. (1)Sengoku daimyo theory

     I see the Warring States period as an era when Japan was divided into multiple nations (nations by Sengoku daimyo). In the territory of the Sengoku daimyo, there is a miniature Sengoku daimyo called "Kunishu" who has been granted autonomy. I think that the relationship between Sengoku daimyo and "Kunishu" is similar to the relationship between the Edo Shogunate and Daimyo. The goal is to clarify the position of Japanese history during the Warring States period.

  2. (2)Diplomatic negotiations between Sengoku daimyo and the diplomat in charge of it

     I consider the Sengoku daimyo to be one nation, and position negotiations between the Sengoku daimyo as "diplomatic". In the diplomacy between daimyo, each senior vassal acted as an "agency" and proceeded with negotiations. By examining the specific development and the characteristics of the "agency", it is clarified that the power of the Sengoku daimyo is supported by the vassals.

  3. (3)Transitional research from the Middle Ages to the early modern period in Japan

     From the 1450s, which is the middle of the Muromachi period and the beginning of the Warring States period, to the 1650s, which is the beginning of the Edo period, we regard the period from the Middle Ages to the early modern period. I don't think that the reforms by some powerful people, such as Nobunaga Oda and Hideyoshi Toyotomi, have brought about the early modern period. The working hypothesis is the gradual change that the era of the Middle Ages has ended and the era of the early modern period has begun due to the accumulation of social changes that have occurred over the last 200 years. It is similar to the "long 16th century" in European history.

  4. (4)Diplomatics(Historical materials)

     Japanese ancient writing has progressed mainly in the ancient Ritsuryo nation and the Kamakura period. However, the reality is that there is little accumulation of paleographies from the late Middle Ages to the early modern period. The ancient document studies of the Sengoku daimyo vary greatly from region to region, and are limited to individual case reports. The major challenge is to systematize the ancient writing studies of the Sengoku daimyo and the Oda and Toyotomi administrations.

  5. (5)Research on the memorial service request rearranging book (past book) from Koyasan

     At the temples (shukubo) that make up Koyasan, there is a list of memorial services requested from all over Japan. Unlike the past books of general temples, not only the mourning of the dead, but also the memorial service of living people occupies most of them. Records from the Warring States period remain, and it is a valuable consideration for knowing the names, places of residence, and death dates of influential people in each region, but it has hardly been investigated. We are proceeding with the investigation and introduction, and research on the characteristics as historical materials.

Representative Papers
  1. (1)An unusual letter with the other party's real name written on the address: How to write a letter called "Nijigaki". KOMONJO KENKYU(The Japanese Journal of Diplomatics) No.89. December 2019.
  2. (2)Transition of "Kunishu" to vassals in the Uesugi clan: Using Kitajo clan and Mouri-Yasuda clan as materials. Sengoku daimyo and "Kunishu": Mechanism of domination, subordination, and independence(Edited by Sengokushi-kenkyukai). Published by Ebisukosyo Publication. December 2018.
  3. (3)"Origami", which is a stack of two sheets of paper: Breaking away from a certain belief. A discourse on paper in historical documents(Edited by Yuyama kenichi). Published by Benseisha Publishing. September 2017.
  4. (4)Structure of the "diplomacy" of the Hojo clan and the Tokugawa clan. THE BULLETIN OF THE NATIONAL INSTITUTE OF JAPANESE LITERATURE Archival StUdies Vol.11. March 2015.
  5. (5)Relationship between Sengoku daimyo Takeda's western rule of Kozuke Province and the acting Minowa castle: Focusing on the examination of "Knowledge of the acting castle owner" addressed to Masaaki Naito. Chihoshi-kenkyu Vol.64 No.3. June 2014.
  6. (6)Study of Hokuriku rule of Oda power. Oda power territory domination(Edited by Sengokushi-kenkyukai). Published by Iwata-Syoin. April 2011.
  7. (7)Power structure of the Sengoku daimyo Takeda clan. Published by Shibunkaku Publishing. February 2011.
  8. (8)Basic consideration of Sagara's traditional book "Yatsushiro Diary (Chronicle)" owned by Keio University. KOMONJO KENKYU(The Japanese Journal of Diplomatics) No.65. May 2008.
  9. (9)A study of the territorial ruler "Gunji" of Sengoku daimyo Takeda: Taking the rule of Suwa-gun, Shinano Province as an example. Shigaku Vol.75 No.2-3 merger. January 2007.
  10. (10)Agent in charge of diplomacy of the Sengoku daimyo Takeda clan:As an example, the alliance between Takeda clan and Uesugi clan . Takedashi-kenkyu. No.22. March 2000.
Grant-in-Aid for Scientific Research Support: Japan Society for Promotion of Science (JSPS)
Recruitment of research assistant(s) No
Affiliated academic society (Membership type) (1)Society for the Study of Diplomactis in Japan(Editorial committee secretary)
(2)Sengokushi kenkyukai(Committee member,Former Executive Secretary)
(3)Takedashi kenkyukai(Vice Chairman, Editor-in-Chief)
(4)MIta shigakkai(General member)
(5)Chihoushi kenkyu kyougikai(General member)
(6)The Japanese Society for Historical Studies(General member)
(7)Nihon Rekishi gakkai(General member)
(8)Historical Science(General member)
(9)The Osaka Historical Association(General member)
(10)Shokuhouki kenkyukai(General member)
(11)The Shinano History Society(General member)
(12)Shizuokaken chiikishi kenkyuukai(General member)
(13)Shikoku chuseishi kenkyukai(General member)
(14)Kyushushigaku kenkyukai(General member)
(15)Nanakuma shigakkai(General member)
(16)Mita chuseishi kenkyukai(Former representative)
Education Field (Undergraduate level) Japanese history,Cultural history,Sengoku daimyo theory