一隅を照らす ichigū o terasu Light Up Your Own Corner
一隅を照らす (ichigū o terasu) means: light up one corner. It is how the Tendai school reads four characters the monk Saichō wrote in 818 about who is the treasure of a nation. In his own hand the second character looks less like 于 than like 千, a thousand, and the line then asks for more.
Abstract
一隅を照らす, light up one corner, is the Tendai school's reading of four characters in the Regulations for Annual Students, 天台法華宗年分学生式, which the monk Saichō 最澄 presented to the court in 818, in a passage on the treasure of a nation built from a story told in the words of the Tang commentator Zhanran 湛然, of ministers who each guarded a corner of the realm and so lit a thousand li [1][2][3]. The printed editions read for this history, from a commentary of 1811 to the Taishō canon, print 照于一隅, lighting one corner, and the school has read the line so in its movement since 1969 and by its ruling of 1974 [1][4][5]. Saichō's manuscript survives, and quotations printed the second character as 千, a thousand, from 1902 in the prints found for this history; the standard edition of 1974 printed 照千一隅 from the manuscript, lighting a thousand li, guarding one corner, and scholars argued over the one character from 1969 into the 1980s [6][7][8][9]. I read the character in the photograph as 千, and I hold the school's 一隅を照らす as the reading the line has lived by.
Overview
The sense. No general dictionary at kotobank enters the line as a headword. 精選版 日本国語大辞典 gives it as the first example of 一隅 in the sense 一方のすみ。片すみ。, one corner; a nook, quoting 照于一隅此則国宝 from the Regulations; デジタル大辞泉's first sense of 一隅 is the same, 一方のすみ。かたすみ。 [10]. The Tendai school's movement explains the 一隅 of the line as 自分の持ち場, one's own post [11], and its English pamphlet says Ichigu means "where you are", not literally a corner [12].
The words. 照 is to shine on, to light. 一隅 is one corner. Between them stands the character in question. Read 于, a preposition, the four characters are 照于一隅, to shine on one corner, and in Japanese 一隅を照らす. Read 千, a thousand, they are 照千一隅, which on the reading of its first editor is two halves of one phrase, lighting a thousand (li) and one corner (guarded) [7][9]. The line goes on 此則國寶, this is the treasure of the nation [1]. The phrase 照一隅 is old Chinese, and in the 淮南子 it is a small light: the 淮南子, of the second century BCE, says 受光於隙照一隅, light that comes in through a crack lights one corner, against light from a window and from a door, and concludes 所受者小則所見者淺, where what is received is small, what is seen is shallow [13]. The Chinese Buddhist canon as CBETA carries it has no 照一隅 at all, and 照千里, to light a thousand li, twenty-seven times [14].
The text in English. The anthology Sources of Japanese Tradition, in 1958: ten pearls big as pigeon's eggs do not constitute the treasure of a nation, but only when a person casts his light over a part of the country can one speak of a treasure of the nation [15].
The historical record
The story behind the line. The 史記 tells it of King Wei of Qi 齊威王: meeting the king of Wei, who boasted of ten pearls an inch across that lit twelve carriages front and back, he said his own treasures were his ministers, set each to guard a city or a border, and ended 將以照千里,豈特十二乘哉, they will light a thousand li; why only twelve carriages? [2]. Zhanran retold it in his commentary 止觀輔行傳弘決 in words that put the two halves of the dispute side by side: 有臣如檀子等,各守一隅,則使楚趙燕等不敢輒前 … 以此為將,則照千里, I have ministers such as Tanzi, each of whom guards one corner, so that Chu, Zhao and Yan dare not advance … make such men generals and they light a thousand li; and he closed 此即能說能行之國寶也, this is the treasure of the nation who can both speak and act [3]. The 史記 has 照千里 and no 一隅; Zhanran has 守一隅 and 照千里; neither has lighting a corner [2][3].
818. The Regulations. Saichō dated the Regulations 弘仁九年五月十三日, the thirteenth day of the fifth month of 818, as part of his petition that Tendai's yearly ordinands be ordained on Mount Hiei and kept there twelve years [1]. The preface, as the Taishō canon prints it from the 伝教大師全集: 國寶何物。寶道心也。有道心人。名爲國寶。故古人言。徑寸十枚。非是國寶。照于一隅。此則國寶。古哲又云。能言不能行。國之師也。能行不能言。國之用也。能行能言。國之寶也。, What is the treasure of the nation? The treasure is the mind that seeks the Way. One who has that mind is called the treasure of the nation. So the ancients said: ten pearls an inch across are not the treasure of the nation; to light one corner, this is the treasure of the nation. And a sage of old said: one who can speak but not act is the nation's teacher; one who can act but not speak is the nation's servant; one who can both act and speak is the nation's treasure [1]. The pearls, the treasure of the nation and the one who can both speak and act are all in Zhanran's paragraph [3].
The hand. Saichō's own copy of the Regulations survives inside a scroll in his hand, the 天台法華宗年分縁起, which the caption of a 1937 plate gives to the temple Enryakuji 延暦寺 (the caption read in the text layer) [16]. In a collotype of the scroll published in 1903, the passage reads 古人言徑寸十枚非是國寶照?一隅此則國寶, and where the Taishō prints 能行能言 the hand writes 能言行能言 [17]. The character after 照 has a long first stroke that falls to the left from the head of the vertical, one horizontal crossing the vertical, and a vertical with no hook [17]. The same hand writes 于 twice in the scroll, in 至于 and 永期于後際, each time with two separate level strokes above and a hooked vertical [17]. A second photograph, printed in 1937, shows the same form [16].
1626 to 1931. The printed texts: 于. The earliest print read for this history, a book of questions and answers on the Regulations printed in 1626, explains 國寶 by Zhanran's story and does not quote the clause (read in the text layer) [18]. The commentator Keikō 敬光, in a commentary with a preface of 1790, printed in 1811, prints 照于一隅 with a reading mark that sends 照 after 一隅, lights one corner, tells the story of King Wei in Zhanran's words and closes 事見史記今取此意, the matter is in the 史記; here its sense is taken [4]. On the next leaf he quotes an earlier commentary: 世間國寶其所照處不過千里菩薩國寶遍照十界, the world's treasure lights no more than a thousand li; the bodhisattva who is the nation's treasure lights all ten realms [4]. A print of the Regulations of 1897, the 伝教大師全集 of 1912 and the Taishō canon of 1931 print 照于 [19][20][1]. The book of Saichō's disciple Kōjō 光定, which copies the passage, reads 照十一隅 in its print of 1664, and the 全集 notes at that word 十一式作于一, for 十一 the Regulations write 于一 [21].
1902 to 1966. The other form in print: 千. Long before anyone argued for it, the passage was printed with 千. A lawyers' association journal printed 照千一隅、此則國寳 in December 1902, and the historian of Buddhism 大屋徳城 printed 照千一隅 in 1928 [6][22]. Before the school's movement the line was a motto in business and civic life, written 照千一隅 and read 一隅を照らす: a 1959 directory gives a mining company director's motto as 「照千一隅」(伝教大師「山家学生式」より(一隅を照す、此れ則ち国宝なり)), and a 1964 book quotes a newspaper piece of 1963 in which a man has kept 「一隅を照らす」(照千一隅) as his motto for more than twenty years [23][24]. The school's own office of doctrine, 天台宗教学部, issued a pamphlet in the 1960s with the title 『照千一隅』 (a catalogue entry) [25].
1965 to 1969. The movement. By the school's own chronology, a meeting of its scholars on 20 May 1965 adopted 照于一隅運動 as a policy of teaching, and the 一隅を照らす運動, the Light Up Your Corner Movement, was founded on 20 June 1969 to spread the founder's words 一隅を照らすこれ則ち国宝なり [5][26]. A history of the movement for its thirtieth year, in 1999, gives the reason for the plain Japanese: 照于一隅では解りにくかろう, 照于一隅 would be hard to understand, and the movement was an appeal to people of the day [27].
1969 to 1974. The dispute. At the school's own scholarly meeting in 1969, the priest Kimura Shūshō 木村周照 gave a paper on problems in the school's teaching, particularly 一隅を照らす; as printed in 1970 it says that the movement takes the words as the reading of 照于一隅, but in the founder's autograph … the 于 is clearly 千 [8]. He pressed it in the school's journal through the next years, against the scholar Fukui Kōjun 福井康順 [28][29]. The Tendai ascetic Hagami Shōchō 葉上照澄 wrote in 1971 that the scroll in fact writes 照千一隅 and that the school says 照于一隅 [30]. In May 1974 (the month as Noguchi gives it [9]) the historian Sonoda Kōyū 薗田香融 printed 照千一隅 in the standard edition of Saichō, 日本思想大系 4, with a note that it had been read 照于 and 一隅を照す and that this was not right: 「照千」は「照千里」の略であり、「一隅」は「守一隅」の略であることは明らかである。したがって、「照千一隅」を「千の一隅を照す」と訓むこともできないし、いわんや「一隅を照す」と訓むことも不可能である, it is clear that 照千 abbreviates 照千里 and 一隅 abbreviates 守一隅; so 照千一隅 cannot be read "lights a thousand corners", much less "lights one corner" [7]. He wrote later that he had not known Kimura's argument until Kimura's review of the edition in the religious newspaper 中外日報 on 8 June 1974 (as Noguchi quotes him) [9].
1974. The school's ruling. The school answered within weeks. Its highest doctrinal council, the 勧学院, met in late July 1974 and settled on reading 照于一隅 as 一隅を照らす; the movement's pages date the meeting 23 July on one page and 29 July on another, and Sonoda's bibliography lists a newspaper report of 9 August 1974 headed 天台宗勧学院議が再確認, the Tendai council reconfirms [11][5][31]. Fukui read a paper titled 照于一隅が正しい, 照于一隅 is right, to a learned society on 31 July (as Sonoda's bibliography lists it) [31]. In the 1999 history a speaker who had served, in his words, as 一宗の責任者・理事長 said that officially the reading remains 照于一隅 [27].
1975 to 1981. Both sides. Sonoda answered Fukui in 1975, in a paper whose title calls the other reading 「照于一隅」説, and in a further reply to the scholar of Shinto Noguchi Tsuneki 野口恒樹, both reprinted in his book of 1981 [31][9]. As Noguchi quotes him, Sonoda had first taken the character for 于 written in Saichō's own manner, since the 亍 of the many 行 in the Regulations lacks its hook, until he compared the 于 of 永期于後際 in the same manuscript: 『そこでは「于」の字が明瞭に「千」字と区別されています』, there the 于 is clearly distinguished from 千 [32]. Fukui objected that a compression of 守一隅則照千里 should run 一隅照千 (as Noguchi reports him) [32]. Noguchi, who wrote that he had seen only photographs of the scroll, argued that the 亍 of the seven 行 range from a hooked form to the shape of 千, so that the character could be 于 written the same way [32]. Their quarrel was about the treasure as much as the letter. Sonoda, in Noguchi's account of him, took the treasure to be the yearly ordinand of Hiei, called the one who merely lights a corner a 小人物, a small person, and urged the movement to rename itself 照千一隅運動; Noguchi answered that the one who has the mind that seeks the Way is not the ordinand alone but 「一隅を照らす人」, the one who lights a corner, and that the movement could be one 祖師最澄の自語による国宝観に直結する, joined directly to the founder's view of the treasure as put in his own words [9]. The historian Nakai Shinkō 中井真孝, reviewing the year's work in 1976, judged: 「昭千里」「守一隅」をつづめた造語として、「照千一隅」は、漢文上はたしかに破格の表現であるが、著者の自筆であること、原典が明らかで引用の正確なこと、意義が通ること、の三調子がそろえば、薗田氏の説は首肯せざるをえない, as a coinage compressing 照千里 and 守一隅, 照千一隅 is certainly an irregular expression in classical Chinese; but when the three come together, the author's own hand, a clear source accurately quoted and a meaning that makes sense, Sonoda's view has to be accepted (昭千里 and 三調子 as printed) [33]. Kimura collected his papers in 2002 as 『照千一隅論攷』 [34].
Today. The movement's page on the founder's teaching reads 一隅を照らす and explains it by Zhanran's 各守一隅(中略)以此為將則照千里: by guarding one corner, one's own post, a monk lights the corners of the country a thousand li away, and such monks are the treasure [11].
1958 to 2007. The English. Sources of Japanese Tradition, compiled by Ryusaku Tsunoda, Wm. Theodore de Bary and Donald Keene in 1958, renders the clause only when a person casts his light over a part of the country can one speak of a treasure of the nation, and its footnote gives the philosopher of old as Mouzi 牟子 [15]. The same clause, casts his light over a part of the country, is in the anthology's later printings and its second edition of 2001, and in Collcutt's Cultural Atlas of Japan of 1988 (the Internet Archive's full-text search) [15][35]. The movement's own English has he who sheds his light over a corner of the country is the nation's treasure [12]. Stephen Covell, in 2005, calls the movement Light Up Your Corner and dates its founding 1969 [36]; John Koller, in 2007, has Saichō promulgate Ichigu wo Terasu, "Light up a corner of the world" [37]. No English rendering read for this history keeps the 千.
A reading
I read the character in the photograph as 千. My ground is the first stroke. In the same hand, 于 has a short level stroke above a long one, and the 亍 of 行 has a short stroke set apart above its horizontal; the character after 照 has neither, but a long stroke falling left from the head of the vertical [17]. The missing hook proves nothing, as Noguchi saw: the hand often leaves 亍 unhooked [32]. Sonoda read the scroll itself and compared the same 于 [32]; I have read only photographs. On that reading Saichō wrote 照千一隅, and he wrote it out of Zhanran, whose paragraph holds the pearls, the treasure of the nation, the one who can both speak and act, and the phrase 照千里 [3]. The treasure he named was the minister of the old story: one who keeps one corner, and whose light reaches a thousand li.
The other reading is not a mistake to be corrected. It has been printed since 1811 at least, and it is the reading the school chose in 1974 with the 千 in front of it [4][5]. Its own explanation keeps the thousand li inside the corner: guard your post, and the light goes out from it [11]. 照一隅 alone was, in the 淮南子, the small light from a crack in the wall [13]; the reading 一隅を照らす made it the light of the one who does what is needed where they stand, and generations have lived by it. I sign 千 for the hand, and I hold 一隅を照らす as the line's reading in use and its own story. Signed, 典.
Notes
What the photographs can and cannot show. The 1903 collotype and the 1937 plate are photographs of one object, so they are one witness to the hand; whether the 1937 plate is a new photograph is not stated [17][16]. The National Diet Library's machine reading of these and later plates of the scroll also gives 千, and it is one more reading of the same image, not a transcriber's [38]. A 千 in Saichō's own hand, to set beside the character, was not found: the scroll has none, and his copy of Kūkai's catalogue of imported items at Tōji, whose text has 千 in the titles of several scriptures, was not found in any image open to a reader outside Japan.
The 1084 manuscript. Kimura reported in 1973 a manuscript at Enryakuji copied in 1084 by 良祐 that reads 照千一隅 in a clear hand [29]. His later work compares 良祐's copy of Kōjō's book, which suggests that this is the manuscript meant; that is an inference, not a reading.
The date of the ruling. The movement's pages give 23 July 1974 and 29 July 1974 [11][5]. Sonoda's 1981 book mentions 七月二十六日 in a sentence about a statement based on the council [31]. Which day the council met is not settled here.
Japanese Scrolls by Master Calligrapher Eri Takase
Sources not seen
木村周照's papers in 天台学報 12, 14, 15, 20, 22, 29 and 30 at their pages, and his 『照千一隅論攷』 (2002).
薗田香融, 「「照于一隅」説批判」 (仏教史学研究 17(2), 1975) and 「「照千一隅」説再論」, at their pages; 『平安仏教の研究』 (1981) at its pages.
福井康順, 天台学報 16 (1974) and 17 (1975), at their pages.
日本思想大系 4 『最澄』 (1974) at its pages, text, head note and supplementary note.
野口恒樹, 『やはり「一隅を照らす」が正しい』 (1977), and his papers in 神道史研究 23(1) (1975) and 27(2) (1979).
福井文雅, 「「照千(于)一隅」の本義」, 天台学報 31 (1989); 大久保良峻, 「最澄の名言」, 天台学報 56 (2013); 大久保良順's facsimile edition of the 天台法華宗年分縁起.
The 1665 print of the Regulations, which Kimura reports as the earliest with 照于; the commentary 学生式顕正解 that Keikō quotes.
Paul Groner, Saichō: The Establishment of the Japanese Tendai School (1984), and Covell's chapter on the movement at its pages.
A modern photograph of the scroll, and Saichō's copy of the Tōji catalogue at the 千 of its titles.
A reader with access to any of these is invited to write to Takase Studios at Tim@Takase.com.
References
- 最澄, 『天台法華宗年分學生式一首』, 大正新脩大藏經 vol. 74, no. 2377, pp. 623c–624b, at SAT. https://21dzk.l.u-tokyo.ac.jp/SAT/T2377_.74.0623c10:0624a05.cit
- 『史記』 卷46, 田敬仲完世家, at Wikisource (Chinese). https://zh.wikisource.org/wiki/史記/卷046
- 湛然, 『止觀輔行傳弘決』 卷5, T46 no. 1912, p. 279b, at CBETA. https://cbetaonline.dila.edu.tw/zh/T1912_005
- 敬光, 『圓宗學生式貫註』 (三式貫註), preface 寛政2 (1790), printed 文化8 (1811) (the dates are the 国書データベース's record), 京都大学 copy, canvases 15–16, at the 国書データベース. https://kokusho.nijl.ac.jp/biblio/100380690
- 一隅を照らす運動, 「年表」 (chronology), entries for 20 May 1965, 20 June 1969 and 29 July 1974, at ichigu.net. https://ichigu.net/org/chronology.php
- 『日本弁護士協会録事』 60, 28 December 1902 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/11029561
- 安藤俊雄・薗田香融 校注, 『最澄』, 日本思想大系 4, 岩波書店, 1974 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/12223550
- 木村周照, 「現代本宗布教における問題點 : 特に「一隅を照らす」について」, 天台学報 12 (1969 meeting), 1970, pp. 104–112 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/13790323
- 野口恒樹, 「薗田教授の「照千一隅説再論」に反論す」, 皇學館論叢 14(2), 1981, pp. 15–46 (pp. 15–19 and 45 read at the page), at the 皇學館大学 repository. https://kogakkan.repo.nii.ac.jp/records/2000714
- 「一隅」, デジタル大辞泉, 精選版 日本国語大辞典 and 普及版 字通, at kotobank. https://kotobank.jp/word/一隅-433266
- 一隅を照らす運動, 「天台宗の教え」 (the movement's page on the founder's teaching), at ichigu.net. https://ichigu.net/about/
- Ichigu wo Terasu Undo, English pamphlet (2404), at ichigu.net. https://ichigu.net/en/pamphlet-2404.pdf
- 『淮南子』, 說山訓, at Wikisource (Chinese). https://zh.wikisource.org/wiki/淮南子/說山訓 · its date, 中国で前2世紀に成立した書, from 百科事典マイペディア 「淮南子」 at kotobank. https://kotobank.jp/word/淮南子-37013
- CBETA full-text search, 照一隅 (0) and 照千里 (27), run 12 October 2026. https://cbdata.dila.edu.tw/stable/search?q=照一隅 · https://cbdata.dila.edu.tw/stable/search?q=照千里
- Ryusaku Tsunoda, Wm. Theodore de Bary and Donald Keene, comps., Sources of Japanese Tradition, vol. I, Columbia University Press, 1958, p. 127 and note 9, read on the house's shelf in the sixth printing; at the Internet Archive in the printing of 1964. https://archive.org/details/sourcesofjapanes00tsun
- 恩賜京都博物館 編, 『天台霊華』, 小林写真製版所出版部, 1937, scans 162 (caption) and 163, at the National Diet Library. https://dl.ndl.go.jp/pid/8311841/1/163
- 最澄 書, 『羯磨金剛目録・法華年分縁起』, 吉川半七, 1903, scans 6, 12, 13 and 14, at the National Diet Library. https://dl.ndl.go.jp/pid/1088568/1/12
- 『天台法華宗學生式問答』, 延暦寺寶幢院, 寛永3 (1626) print, scans 2–5, at the National Diet Library. https://dl.ndl.go.jp/pid/2532179
- 最澄, 『山家学生式』, 山田常蔵, 1897, at the National Diet Library. https://dl.ndl.go.jp/pid/819332
- 天台宗宗典刊行会 編, 『伝教大師全集』 第1, 1912, at the National Diet Library. https://dl.ndl.go.jp/pid/819607
- 光定, 『傳述一心戒文』, T74 no. 2379, p. 651a, with the head note on its witnesses, at SAT. https://21dzk.l.u-tokyo.ac.jp/SAT/T2379_.74.0650c09:0651a22.cit
- 大屋徳城, 『日本仏教史の研究』 第2巻, 1928 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/1259432
- 『労務経営人』 第1集, 1959 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/3445453
- 中西寛人, 『鋳物に生きる』, 1964, quoting 毎日新聞 14 August 1963 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/12681354
- 国立国会図書館収書部 編, 『全日本出版物総目録』 昭和39年版, 1966, entry 山口光円 『照千一隅』, 天台宗教学部 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/2969133
- 一隅を照らす運動, 「一隅を照らす運動のあゆみ」, at ichigu.net. https://ichigu.net/org/history.php
- 一隅を照らす運動東京本部 他, 『一隅を照らす運動三十周年記念誌』, 1999 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/14033966
- 木村周照, 「布教と宗学 — 一隅を照らす運動を中心として」, 天台学報 14, 1972, pp. 119–126 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/13790319
- 木村周照, 「照于一隅説に関する疑問 — 福井博士のご所見を中心として」, 天台学報 15, 1973, pp. 52–60 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/13774756
- 葉上照澄, 『道心』, 1971 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/12240208
- 薗田香融, 『平安仏教の研究』, 1981 (snippet view, National Diet Library). https://dl.ndl.go.jp/pid/12220683
- 野口恒樹, 「「照千一隅」説の矛盾と誤謬」, 皇學館論叢 8(5), 1975, pp. 27–40, read at the page, at the 皇學館大学 repository. https://kogakkan.repo.nii.ac.jp/records/2000567
- 中井真孝, 「日本 古代 四」, 史学雑誌 85(5) (一九七五年の歴史学界 : 回顧と展望), 1976, p. 572, at J-STAGE. https://www.jstage.jst.go.jp/article/shigaku/85/5/85_KJ00003649299/_article/-char/ja/
- 木村周照 編著, 『照千一隅論攷 : 伝教大師最澄の真意を問う』, 2002, at CiNii. https://cir.nii.ac.jp/crid/1971712334757157910
- Martin Collcutt, Marius Jansen and Isao Kumakura, Cultural Atlas of Japan, Facts on File, 1988 (the Internet Archive's full-text search). https://archive.org/details/culturalatlasofj00mart
- Stephen G. Covell, Japanese Temple Buddhism: Worldliness in a Religion of Renunciation, University of Hawai'i Press, 2005 (the Internet Archive's full-text search). https://archive.org/details/japanesetemplebu0000cove
- John M. Koller, Asian Philosophies, Pearson Prentice Hall, 2007 (the Internet Archive's full-text search). https://archive.org/details/asianphilosophie0000koll
- NDL Lab full-text search, 照千一隅, run 12 October 2026. https://lab.ndl.go.jp/dl/api/book/search?searchfield=contentonly&keyword=照千一隅




