Overview
Suisaki is a diary written by Minamoto no Toshifusa, a high-ranking court official (kugyō) during the late Heian Period. The title itself combines the author’s surname, “Minamoto” (rendered here as suizui or ‘water’), and his official post, Sa Daijin (Left Minister of State). It is also known by alternative titles such as Toshifusa Kōki or Safu-ki. This document is an extremely valuable historical source because it provides a detailed account of the court society during a transitional period—moving from the powerful regency politics (Sekkari Seiji) to the imperial rule (Insei) exercised by retired emperors.
Historical Background
The author, Minamoto no Toshifusa (1035–1121), was a practical and influential official who served as Left Minister of State for many years during the reigns of Emperor Shirakawa and Emperor Horigawa. The original manuscript designated as a National Treasure contains records from key years: 1081 (Eihō 1), 1082 (Eihō 2), and 1088 (Kanji 2). This period marked a major transformation in the political structure of the Imperial Court. Consequently, this manuscript is an essential primary source for understanding the political decision-making processes and social conditions of the time.
Features and Appeal
The greatest feature of this work is that it exists as an “original manuscript” (jihon) written by Minamoto no Toshifusa himself.
- Rare Original Manuscript: While many diaries from the Heian Period survive only through later copies, finding direct writings from a powerful official in the 11th century is exceptionally rare. This rarity is the primary reason for its designation as a National Treasure.
- Guide to Court Protocol: The diary details court rituals, public affairs, and customs. These records were highly valued by subsequent aristocratic families (kuge) who used them as models (yūshoku kojitsu) for learning proper ceremonial etiquette.
- Importance of Back-of-Paper Documents: The reverse side of the manuscript contains reports and letters from local officials (juryō) and from Taira no Masamori, an ancestor of the rising Isehei clan. These documents are valuable byproducts that provide insights into regional governance and samurai movements, possessing historical value equal to or greater than the diary itself.
- Excellent Preservation: It has been preserved and managed by the Maeda Ikutoku Foundation as a treasure within the “Sonkeikaku Library.” The manuscript transmits the essence of Heian Period document culture to modern times.
Source: Excerpted from the National Designated Cultural Properties Database (https://kunishitei.bunka.go.jp/bsys/index)