Stroke (CJK character)


CJK strokes are the calligraphic strokes needed to write the Chinese characters in regular script used in East Asian calligraphy. CJK strokes are the classified set of line patterns that may be arranged and combined to form Chinese characters in use in China, Japan, and Korea.

Purpose

The study and classification of CJK strokes aid in:
  1. understanding Chinese character calligraphy – the correct method of writing, shape formation and stroke order;
  2. understanding stroke changes according to the style that is in use;
  3. defining stroke naming and counting conventions;
  4. identifying fundamental components of Han radicals; and
  5. their use in computing.

    Formation

When writing Han radicals, a single stroke includes all the motions necessary to produce a given part of a character before lifting the writing instrument from the writing surface; thus, a single stroke may have abrupt changes in direction within the line. For example:
All strokes have direction. They are unidirectional and start from one entry point. People should not write them in the reverse direction. Here are some examples:

Types

CJK strokes are an attempt to identify and classify all single-stroke components that can be used to write Han radicals. There are some thirty distinct types of strokes recognized in Chinese characters, some of which are compound strokes made from basic strokes. The compound strokes comprise more than one movement of the writing instrument, and many of these have no agreed-upon name.

Basic strokes

A basic stroke is a single calligraphic mark moving in one direction across a writing surface. The following table lists a selection of basic strokes divided into two stroke groups: simple and combining. "Simple strokes" can be written alone. "Combining strokes" never occur alone, but must be paired with at least one other stroke forming a compound stroke. Thus, they are not in themselves individual strokes.
Note, the basic stroke Diǎn "Dot" is rarely a real. Instead it usually takes the shape of a very small line pointing in one of several directions, and may be long enough to be confused with other strokes.

Compound strokes

A compound stroke is produced when two or more basic strokes are combined in a single stroke written without lifting the writing instrument from the writing surface. The character "eternity" described in more detail below demonstrates one of these compound strokes. The centre line is a compound stroke that combines three stroke shapes in a single stroke.
;Basics for making compound strokes
In most cases, concatenating basic strokes together form a compound stroke. For example, Vertical / Shù combined with J hook / Gōu produce . A stroke naming convention sums the names of the basic strokes, in the writing order.
An exception to this applies when a stroke makes a turn of 90° in the Simplified Chinese names. Horizontal and Vertical strokes are identified only once when they appear as the first stroke of a compound; any single stroke with successive 90° turns down or to the right are indicated by a Zag 折 "Break". For example, an initial Shù followed by an abrupt turn right produces . In the same way, an initial Shù followed by an abrupt turn right followed by a second turn down produces . However, their inherited names are "Vertical – Horizontal" and "Vertical – Horizontal – Vertical". We need not to use "Zag" in the inherited names.
Nearly all complex strokes can be named using this simple scheme.

Nomenclature

Organization systems used to describe and differentiate strokes may include the use of roman letters, Chinese characters, numbers, or a combination of these devices. Two methods of organizing CJK strokes are by:
  1. Classification schemes that describe strokes by a naming convention or by conformity to a taxonomy; and
  2. Categorization schemes that differentiate strokes by numeric or topical grouping.
In classification schemes, stroke forms are described, assigned a representative character or letterform, and may be arranged in a hierarchy. In categorization schemes, stroke forms are differentiated, sorted and grouped into like categories; categories may be topical, or assigned by a numeric or alpha-numeric nominal number according to a designed numbering scheme.
;Benefits
Organizing strokes into a hierarchy aids a user's understanding by bringing order to an obtuse system of writing that has organically evolved over the period of centuries. In addition, the process of recognizing and describing stroke patterns promotes consistency of stroke formation and usage. When organized by naming convention, classification allows a user to find a stroke quickly in a large stroke collection, makes it easier to detect duplication, and conveys meaning when comparing relationships between strokes. When organized by numbering scheme, categorization aids a user in understanding stroke differences, and makes it easier to make predictions, inferences and decisions about a stroke.
;Limitations
Strokes are described and differentiated using the criteria of visual qualities of a stroke. Because this can require subjective interpretation, CJK strokes cannot be placed into a single definitive classification scheme because stroke types lack a universal consensus on the description and number of basic and compound forms. CJK strokes cannot be placed into a single definitive categorization scheme due to visual ambiguity between strokes, and therefore cannot be segregated into mutually-exclusive groups. Other factors inhibiting organization based on visual criteria is the variation of writing styles, and the changes of appearance that a stroke undergoes within various characters.

Roman letter naming convention of Unicode standard

A naming convention is a classification scheme where a controlled vocabulary is used systematically to describe the characteristics of an item. The naming convention for a CJK stroke is derived from the path mark left by the writing instrument. In this instance roman letters are concatenated to form a stroke name is a sequence of one or more roman letters indicating the component strokes used to create the CJK stroke. The first letter of the Han radical’s pinyin pronunciation represents each basic stroke. In a basic stroke example, H represents the stroke named 横 ; in a compound example, HZT represents 横折提.
While no consensus exists, there are up to 12 distinct basic strokes that are identified by a unique Han radical.
LetterBDGHNPQSTWXZ
Stroke direction
Simp./Trad./////
PinyinBiǎnDiǎnGōuHéngPiěQuānShùWānXiéZhé
Meaning"Flat""Dot""Hook""Horizontal""Press down""Throw away""Circle""Vertical""Rise""Bend""Slant""Break"

There are many CJK compound strokes, however there is no consensus for sequence letter naming of compound strokes using the basic strokes. The following table demonstrates the CJK stroke naming convention:
StrokeName in PRCAbbrFull NameDictionary meaning and NoteExample charactersEncoding
HHéng , "cardinal number one", "alone".二 三 丁 丞 丈 世 不 上 十 卅 七U+31D0
T 冰 淋 病 孑 治 冶 冽 暴 氾 录 地 虫U+31C0
横钩HGHéng Gōu wān, ya, zhé turning stroke / to break.疋 了 危 予 矛 子 字 令 疏 写 冖U+31D6
横撇HPHéng Piě 又 水 夕 径 炙 双 叒 今U+31C7
横折HZHéng Zhé 口 囗 己 田 品 吕 申 甲 圆 巪U+31D5
横折钩HZGHéng Zhé Gōu.羽 习 包 勻 葡 用 青 甫 勺 月 也 乜U+31C6
横折提HZTHéng Zhé Tí 讠 计 鳩U+31CA
横折折HZZHéng Zhé Zhé U+31C5
横折弯HZWHéng Zhé Wān 殳 投 朵U+31CD
横折弯钩
HZWG
Héng Zhé Wān Gōu
Unofficial name "HWG" is used by Hugo Lopez.飞 风 瘋 凬 虱 迅 气 九 几U+31C8
横斜弯钩
HXWG
Héng Xié Wān Gōu
yǐ, niè, "the second of the ten heavenly stems", "second"; zhé turning stroke / to break.氹 乞 乤 艺U+31E0
横折折折HZZZHéng Zhé Zhé Zhé U+31CE
横折折撇HZZPHéng Zhé Zhé Piě 建 及U+31CB
横撇弯钩HPWGHéng Piě Wān Gōu 队 邮U+31CC
横折折折钩HZZZGHéng Zhé Zhé Zhé Gōu nǎi, archaic form of "then", "really, indeed", "namely", "you, your".乃 孕 仍U+31E1
SShù , gǔn, "vertical line".丩 中 串 讧 乍 上 五 丑U+31D1
竖钩SGShù Gōu jué, "a vertical line with a hook".爭 事 求 水U+31DA
竖提STShù Tí 以 比 切 卯 食 良 艮 很 狠 鄉 民U+31D9
竖折SZShù Zhé 断 陋 继 山 互 彙 牙 乐 东U+31D7
竖弯SWShù Wān 區 亡 妄 四U+31C4
竖弯左SWZShù Wān Zuǒ 肅 嘯 蕭 簫U+31D8
竖弯钩SWGShù Wān Gōu yǐn, "hidden", "mysterious", "small", usually read as / yǐn.乱 己 已 巳U+31DF
竖折折SZZShù Zhé Zhé 亞 鼎 卐 吳 专U+31DE
竖折弯钩
SZWG
Shù Zhé Wān Gōu
亏 强 弓 丏 丐 与 马 鸟 丂 号U+31C9
PPiě usually read as 撇 piě, "line", "slash".乂 爻 禾 毛 乏 乖 釆 衣 八 行U+31D2
竖撇SPShù Piě 乃 月 用 齊 几 人 班 大U+31D3
撇钩PGPiě Gōu U+31E2
撇折PZPiě Zhé 弘 玄 公 厶 翁U+31DC
撇点PDPiě Diǎn quǎn, a little drain between fields, usually read as quǎn.女 巛 巡 獵 災 甾U+31DB
DDiǎn zhǔ, "dot", usually read as 點 / 点 diǎn.丸 叉 义 永 冰 凡 丹 主 求 火 刃U+31D4
N㇏ usually read as 捺 nà.大 人 天 入 走 边 廷 尺U+31CF
提捺TNTí Nà , "stretch". , "to move".尐 之 道 八 入 廻U+31DD
斜钩XGXié Gōu 戈 弋 戰 我U+31C2
扁斜钩BXGBiǎn Xié Gōu 心 必 沁 惢 蕊U+31C3
弯钩WGWān Gōu 狐 狱 豹 家 啄 嶽 貓 家 逐U+31C1
QQuān líng, "zero"; also read as quān, "circle".〇 㔔 㪳 㫈U+31E3

Besides, some strokes have been unified or abandoned in Unicode:
StrokeName in PRCAbbrFull NameNoteExample characters
横撇弯HPWHéng Piě WānIt only appears in Regular script, can be merged into stroke HPHP in Song typeface.辶 过 边
竖折撇SZPShù Zhé PiěThis stroke has been merged into stroke SZZ in Unicode.专 ? ? ?
竖折折弯钩SZZWGShù Zhé Zhé Wān GōuThis stroke has been merged into stroke SZZG in Unicode.弓 丐
WWānIt never occurs alone, only appears inside compound strokes.辶 豕 ?
弯钩WGWān GōuIt never occurs alone, only appears inside compound strokes.
点捺DNDiǎn NàThis stroke has been merged into stroke TN or N in Unicode.內 全 廴
平捺PNPíng NàThis stroke has been merged into stroke N in Unicode.是 走 廴
提平捺TPNTí Píng NàThis stroke has been merged into stroke N in Unicode.辶 之 辷

Notice that some names in the list have not followed the rules of controlled vocabulary. For example, stroke P is not found in the compound stroke PN. The name "PN" comes from 平捺, not 撇捺. The meaning of 平 is flat. So we should call it "BN" 扁捺 if we follow the rule strictly. Letter "Z" in stroke SWZ means 左, not 折. The meaning of 左 is "left", it is not defined in the naming convention. Moreover, some 折 are far more than or far less than 90°, such as stroke HZZZG, stroke HZZP and stroke PZ.
Some strokes are not included in the Unicode standard, such as stroke,,,,,, etc.
In Simplified Chinese, stroke TN is usually written as .

Abbreviation form naming convention of inherited names

On the other hand, naming convention that use abbreviation form of the CJK strokes is also created. After the names of CJK strokes are translated into English, first letters of the English names are used in the naming system. We can divide the controlled vocabulary into two groups.
The first group is Abbreviation form of the basic strokes.
Abbr formHVTPDUCAJO
Shape of stroke
English nameHorizontalVerticalThrowPressDotUpward
horizontal
Clockwise
curve
Anticlockwise
curve
J hookOval
Chinese name

The second group is Abbreviation form of deformations.
Abbr formFWSLRENIMZ
Deformation
English nameFlatWiltedSlantedLeftRightExtendedNarrowedInvertedMirroredZag
Chinese name

“Zig” can be omitted in the naming system. The following table demonstrates the CJK stroke naming convention:

Numbering scheme

A numbering scheme is a categorization method where like-item strokes are grouped into categories labeled by nominal numbers. Category numbering may be an index of numbers of types, with sub-types indicated by decimal point followed by another number or a letter.
The following table is a common numbering scheme that uses similar names as the roman letter naming convention, but the stroke forms are grouped into major category types, which further break down into 25 sub-types in category 5.
Some strokes are not included in the numbering scheme, such as stroke,,,,,,,, etc.
Besides, ways of grouping strokes are different from the Unicode standard. For example, stroke is merged into stroke in Unicode system, while it is merged into in this numbering scheme.

Stroke order

Stroke order refers to the order in which the strokes of a Chinese character are written. A stroke is a movement of a writing instrument on a writing surface. Because most Chinese characters have many strokes, certain stroke orders guidelines are recommended to ensure speed, accuracy, and legibility in composition. Also, teachers enforce exactly one stroke order for each character, marking every deviation as a mistake, so everyone writes these characters the same way. The stroke order follows a few simple rules, though, which aids in memorizing these. To write CJK characters, one must know how to write CJK strokes, and thus, needs to identify the basic strokes that make up a character.

Eight Principles of Yong

The Eight Principles of Yong explain how to write eight common strokes in regular script which are found all in the one character, . It was traditionally believed that the frequent practice of these principles as a beginning calligrapher could ensure beauty in one's writing.
, "eternity". Enlarge this image to see the red arrows, showing the way of writing of each.
;Eight basic strokes

Use in computing

The stroke count method is based on the order of strokes to input characters on Chinese mobile phones.
As part of Chinese character encoding, there have been several proposals to encode the CJK strokes, most of time with a total around 35~40 entries. Most notable is the current Unicode block “CJK Strokes”, with 36 types of strokes: