1. Bushu 部首 as section headers in kanji compilation
In 100 AD, Kyoshin (許慎 Xu Shen in Chinese) compiled 9353 kanji and 1163 variant forms in Setsumon kaiji (説文解字 Shuowen Jiezi in Chinese) by putting all kanji in seal-style forms that had the same common partial shapes into 540 sections (部). Each section had a header (首); thus, the method of this classification is called 部首 bushu (bushou in Chinese) “section header; section index.” The photo on the right shows two pages from the version by Xú Xuàn (徐鉉, 916–991) (Online database link at Waseda University Library at the bottom). On the right page, the third line gives bushu ukanmuri with its explanation. The entry kanji starts in line 5 in seal-style. We see some kanji that became Joyo kanji in Japanese, such as 家宅室宣向, and on the left page, we see 奥宛宇院. By analogy with western (or Romance) language analysis in which a word is treated as comprising a constant component as a root (radical) and a variable component as inflection, bushu are termed “kanji radical” in English. The present-day kanji dictionaries in Japanese usually use slightly over 200 bushu, depending on the dictionaries
2. Top twenty most-used bushu
The distribution of approximately a little over two hundred bushu seen in many kanji dictionaries is extremely lopsided, ranging from 118 entry kanji to 1 entry kanji per a bushu. The top ten most frequently appearing bushu covers 776 kanji, which amounts to 36% of the Joyo kanji. They are: (1) 氵(水) bushu sanzui “flowing water,”appearing in 118 kanji; (2) イ(人) bushu ninben “an act that a person does,” 99 kanji; (3) 扌(手) bushu tehen “an act done by hand,”95 kanji; (4) 木 bushu kihen “tree, wood; wooden,” 85 kanji; (5) three variations of “heart, mind,” 心 bushu kokoro,忄 risshinben, and 㣺 shitagokoro, 76 kanji; (6) 口 bushu kuchi/kuchihen “mouth, a box of prayers,” 70 kanji; (7) 言 bushu gonben “word, language; to say,” 69 kanji; (8) 糸 bushu ito/itohen, 64 kanji; (9) 辵 (辶) bushu shinnyuu/shinnyoo, 51 kanji; and (10) 土 bushu tsuchi/tsuchihen, 49 kanji.
If we include the next top ten appearing bushu, altogether, the top 20 bushu cover more than half (53%) of Joyo kanji. The next 10 most appearing bush are: (11) 艹 bushu kusakanmuri “plants, grass,” 47 kanji; (12) 月(肉) bushu nikuzuki “part of the body,” 44 kanji; (13) 貝 bushu kai/kaihen “cowrie, money, valuable,” 38 kanji; (14) 宀 bushu ukanmuri “house,” 37 kanji; (15) 日 bushu hi/hihen “the sun, bright,” 37 kanji; (16) 女 bushu onna/onnahen “woman, female, feminine,” 36 kanji; (17) 金 bushu kane/kanehen “metal,” 33 kanji; (18) 刀刂 bushu katana/rittoo “sword, knife,” 32 kanji; (19) 阝 bushu kozatohen “tall hills, mountains, boundary, ladder,” 31 kanji; and (20) 火灬 bushu hihen, rekka “fire,” 25 kanji.
Twenty bushu covering a little over half of all Joyo kanji is encouraging to us in the sense that we only need to learn a small number of bushu. On the other hand, when a single frequently appearing bushu has so many kanji entries, it loses the use of discriminating many kanji. Knowledge of some bushu is helpful at the beginning level of kanji study, but beyond that, we have to look for other ways to strengthen our recognition and analytical skills. I will come back to this later.
3. Bushu names are in Japanese
Names of bushu are just nicknames given historically by educators and scholars for the ease of identifying a particular kanji in Japanese. For instance, (1) Hen (偏) means “a part on the left side,” such as イ ninben, 彳 gyooninben “corssroads,” 禾 nogihen “rice crop,” ネ shimesuhen “religious matter,” 扌 tehen, 犭 kemonohen “animal,” 阝 kozatohen, 忄 risshinben, 衤 koromohen “clothes, collar.” (2) Kanmuri (冠) means “a crown,” such as 宀ukanmuri, 艹 kusakanmuri, 癶 hatsugashira “ready to start,” and 耂 oigashira “old person.” (3) Tare (垂れ) means “dangling, hanging” such as 疒 yamaidare “sick,” 厂 gandare “cliff,” 广 madare “eaves, canopy” and 尸 shikabane “dead body, roof, a slumped person, buttock.” (4) Nyoo (繞) means “clinging around,” such as 廴 ennyoo “to extend,” 辶 shinnyuu/shinnyoo, and 儿 ninnyoo “person.” (5) Tsukuri (旁) means the component “on the right side,” such as 攴/攵 bokuzukuri/nobun “to cause an action,” 殳 hokozukuri/rumata “to hit,” 刂 rittoo, and 阝oozato “town.”
Do we need to know the name of the bushu? I would say that knowing some names can be helpful when identifying a particular kanji in communication with other people, but beyond that, it is not that important. The important thing is to recognize the shape and its meaning.
4. Bushu are based on kyuji
Using the traditional kanji dictionary, you may encounter some kanji listed in an unexpected bushu. This is due to the fact that bushu classification is based on kyuji 旧字 (used before 当用漢字 in 1946, precedents of Joyo kanji in 1981.) Some kanji that you are likely to encounter are: Bushu 耳 for the kanji 声 from the kyuji 聲; bushu 至 for the kanji 台 from the kyuji 臺; bushu 黒 for 党 from the kyuji 黨; bushu 黑 for the kanji 点 from 點; bushu 曰 for the kanji 会 from the kyuji 會; bushu 虎 for the kanji 号 from the kyuji 號; bushu 臼 for the kanji 旧 from the kyuji 舊; bushu 貝 for the kanji 売 from the kyuji 賣, etc. There are kanji dictionaries that use new shapes as bushu based on shinji. Also for the order of kanji entry, some kanji dictionaries use bushu, and some use on-reading.
I used to encourage my former students to learn bushu with supplementary study materials because their textbooks did not teach bushu at all. I said bushu told us general semantic background information, and it was very useful. But as we have seen in (2) in this posting, when a particular bushu appears in so many kanji, it can lose its effectiveness, and for more advanced learners we need to look further. In the upcoming study guide for Joyo kanji (tentatively entitled The Key to All Joyo Kanji), 433 common shapes are discussed with their kanji entries. Approximately 3 out of 10 kanji used traditional bushu as the common shapes. The rest is discussed with the components from other recurring components. The manuscripts are in the final proofreading stage. When it is all done, I hope to be able to share with our readers the sample of the list of the common shapes. I appreciate your patience. Thank you very much for your reading. -Noriko (April 24, 2022)
The photo of Setsumon Kaiji: 許慎, 徐鉉「説文解字」 Place and year of publication: unknown https://archive.wul.waseda.ac.jp/kosho/ho04/ho04_00023/ho04_00023_0003/ho04_00023_0003.pdf
Page 26 Waseda University Library