June 03, 2024 TOPICS

[Ambitious Graduate Students] Crown Princes in Medieval Japan: Uncovering the Real Story through their Behavior and Academic Pursuits

Keisei Sano (a second-year doctoral student in the Graduate School of Letters)

Did you know there is no crown prince in Japan who is a direct descendent of the Emperor? Crown prince (kōtaishi in Japanese) means the prince who is first in line to succeed the imperial throne. Since Emperor Naruhito has no sons, there is no kōtaishi. The term kōtaishi first came into use in Japan at the end of the seventh century.
So, what positions did crown princes hold back then? Keisei Sano, a second-year doctoral student in the Graduate School of Letters, is conducting research to shed light on the attributes of crown princes from their behavior in rituals and what they studied in preparation therefor. Because there is almost no prior research on this topic, he must examine every historical document on his own. We sat down with Sano to discuss the challenges he faces in this research, which at times can feel like “grasping at clouds.”

The crown prince system introduced from China

On November 8, 2020, a ceremony called the rikkōshi-no-rei was held, in which Prince Fumihito, the younger brother of the Emperor, was granted the title of kōshi (which is also translated as “crown prince” in English) and was proclaimed the heir to the imperial throne. However, this was the first time in Japan’s long history that such a ceremony was performed, as all previous ceremonies were rikkōshi-no-rei (that is, ceremonies proclaiming the son of an emperor as crown prince and heir to the throne). In the rikkōshi-no-rei performed in 1991, Naruhito was granted the title of Crown Prince (kōtaishi) when his father Akihito (now, the Emperor Emeritus) ascended to the imperial throne. Sano explains:

“In the Imperial House Law, the crown prince is defined as follows: ‘The son of the Emperor who is the Imperial Heir is called kōtaishi.’ Therefore, although Prince Akishino has been declared the heir to the throne and given the title of kōshi, he is not the kōtaishi. This is why the name of the ceremony that was performed was different. The crown prince (kōtaishi) system was introduced to Japan from China around 700 A.D. Prior to that, there was no crown prince system in Japan. Therefore, Prince Shōtoku, who served as a regent of Empress Suiko during the Asuka period (538-710), is not referred to as ‘Crown Prince’, although he was the second son of Emperor Yomei.”

Scholars believe the crown prince system was introduced to ensure a stable succession to the throne. It was thought that making it clear in advance who would be the next emperor would prevent unnecessary conflict. So, what positions did crown princes actually hold? Revealing the realities of crown princes is the subject of Sano's research.

“The crown prince system itself began somewhere between the late Asuka period and the Nara period (710-794), or in the era of ancient Japan, but the focus of my research is on the medieval period that stretches from the mid-to-late Heian period (794-1185) to the Kamakura period (1185-1333). I’m trying to paint a clear picture of the position of crown prince from about 900 A.D. To 1300 A.D.”

Prescribed behaviors and academic pursuits of crown princes

Sano's research focuses on the attributes of crown princes and personnel who supported them. The word “attribute” refers to a special quality only a certain person possesses, so it differs in nuance from terms like “nature” or “character.” Sano decided to use the term “attribute” to demonstrate his strong desire to delve deeper into the true essence of crown princes.

I am focusing on the behavior of crown princes during rituals to identify clues that reveal their attributes. The most important of these ceremonies are the rittaishi-no-rei, which proclaim who the crown prince shall be, and conversely, cases where crown princes were deposed, as well as genpuku, a coming-of-age ceremony, and gyokei, or official outings taken by crown princes. Take the gyokei, for example. The decoration of the vehicle carrying the crown prince and the arrangement of the processions ahead and behind him are all meticulously defined, and naturally there is some kind of meaning behind them. Therefore, I believe that comparing these ceremonies with those of the preceding and following eras will allow me to clarify the attributes of crown princes in medieval Japan."

To add depth to his research, Sano says it is useful to make comparisons with other countries and regions in addition to comparisons across Japan’s regnal eras. To this end, he looked at other countries that had imperial systems, namely China and Korea, as well as the dynasties of Europe.

“Another topic I am exploring is support personnel, that is, the officials who surrounded crown princes. Crown princes were supported by numerous people in administrative positions, such as the tōgū-no-fu and tōgū-gakushi, two types of educational officers. The tōgū-no-fu was the top official who served the crown prince, and was the person closest to him. His role was to provide guidance to the crown prince on matters such as the appropriate ways to behave according to each situation, but to date, scholars have paid little attention to these officials. I have already conducted a detailed study of tōgū-no-fu, which revealed that the activities of these officials and how they were appointed were greatly influenced by the political trends of the time. The roles and actions of the tōgū-no-fu and the tōgū-gakushi, who were the crown prince’s exclusive teachers in a variety of disciplines, are essentially stipulated in the Ritsuryō, or the legal system of the time. For this reason, detailed actions are believed to have changed with each era and depending on the personnel. One example of important historical documents I referred to when exploring these changes are the diaries and writings left by the people of this era.”

Murasaki Shikibu, who penned The Tale of Genji, also wrote The Diary of Murasaki Shikibu. The events described in her account cover the period from 1008 to 1010, and it primarily deals with the state of affairs in the imperial court at that time. These and other writings have proven invaluable to Sano, whose research focuses on the very same time frame. When referring to historical documents like these, however, Sano says that the most important thing to keep in mind is to read diaries on the assumption that they contain the subjective views of their authors. He adds that tales can also be invaluable historical documents if you interpret them on the premise that they contain fictional accounts. Sano refers to these clues, no matter how faint, because so few historical documents that can assist him in his research remain.

Ninkai-Daikyo-Buruiki (National Archives of Japan, formerly in the Nakamikado Family Collection, call number: Ko-034-0589)

“Grasping at clouds:” How Sano pursues his research

Why did Sano choose this research topic in the first place? According to him, the medieval history he is focusing on is something he has been studying since his undergraduate years.

“I wrote my undergraduate thesis on the retired emperors’ official outings to Uji during the period of cloistered rule, when the emperors retained power even after descending the throne. At that time, Uji was politically important as the epicenter of the Regent Houses. After this, I advanced to graduate school where I wanted to choose a topic that had both social and academic significance, so I decided to focus on the attributes of crown princes. I conceived of this topic because I thought it was timely, due to the growing interest in the Imperial Household system in the wake of Emperor Akihito—now Emperor Emeritus—abdicating while he was still alive. With the Imperial Household system at such a critical juncture, I thought it would be useful for future discussions of the system if I could identify the attributes of crown princes. What’s more, as I read through articles on medieval history again, I realized that surprisingly little is known about crown princes in medieval Japan. I drew inspiration from the fact that this topic had not been dealt with much in the past, and I felt it would be a worthwhile pursuit.”

There is an extensive body of research on crown princes in ancient Japan. This is because the position of crown prince was politically important at that time, so there are many historical documents available. As time passed and the medieval era began, however, the political authority of the crown prince was lost. In line with this, interest in the position of crown prince waned, and the research dwindled.

“When you actually look into the articles, you find there are very few studies that focus solely on the position of crown prince in medieval Japan. Although scholars in the past have studied the political significance of crown princes, none of them have narrowed down their focus on the behaviors and other attributes of crown princes. This is why my topic demonstrates originality, something that is required above all else in research. That being said, the lack of prior research means there are no clues from the literature or historical documents that would typically be presented in research papers. In fact, I have not been able to find any historical documents that directly describe the position that crown princes filled.”

Therefore, to move forward with his research, Sano must read every historical document to collect fragmentary descriptions of crown princes and then piece them together. The reason there is no prior research is likely because there were no historical documents that could be easily found. As a scholar, Sano must start by searching for historical documents, but the fact of the matter is that he doesn’t even know where to find them in the first place. Needless to say, it is difficult to conduct this kind of research, but one of the keys to overcoming this barrier, according to Sano, is “communication.”

Encounters with new historical documents lead to new insights

I think it is important to communicate with people who have different views from mine and who have knowledge that I don't have to gain some insights from the limited historical materials. This is because, in many cases, you can gain new insights by holding discussions with people like these. I try to participate as much as possible in on-campus seminars and academic conferences in the Kansai area to diversify my knowledge.”

Of course, the search for historical documents is also essential. Sano visits the University of Tokyo's Historiographical Institute, which is known for its extensive collection of historical documents, as well as other non-university-affiliated research institutions to search for materials.

“In each case, I visit the archives in person, read through the catalogs, and make educated guesses based on the titles. When I start reading the historical documents that I locate in this way, I am usually drawn in at once. Of course, not all of them are helpful, and indeed, there is only a small handful that I can actually use for my research. When you start reading these kinds of historical documents, you can end up getting carried away, so if you don't draw a line somewhere, you will be immersed in documents 24/7. This is how fascinating it is to encounter unknown historical documents, so self-management is vital. If I get sick and it interferes with my research, then it's not worth it.

No matter how much interesting literature he finds, Sano says he always makes sure to get at least the minimum amount of sleep he needs, and his future goal is to become an academic postdoctoral fellow. First and foremost, he wants to complete his doctoral dissertation and earn his degree, and after that, he has a strong desire to teach students as a university faculty member.

In a field where there is no precedent for research, the work that you consistently put in will directly accumulate as research achievements. I believe this to be my greatest strength. My ideal at this point is to become a researcher whose research on crown princes leads to me being asked for my opinions on the imperial system as well.”

Sano is truly a pioneer in the field of historical research, as he is single-handedly blazing a trail through uncharted territory.

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