“Knife” radicals ‘刀’ and ‘刂’ in Chinese writing

Different types of “knife” radicals (www.gearpatrol.com)

Last updated: 28 Apr 2021

This article is part of a compendium of 3500 characters.

(This article has been converted into a course at this Facebook group.)

Please ensure you know these foundational concepts before reading this article:

Keep these 2 reference sources at hand when you read this article:

The first 2 “knife” radicals we will discuss are the straightforward ones. Unlike the third radical ‘⺈’ (radical 12.b), discussed in another article, these 2 “knife” radicals always mean “knife”.

However, various connotations extend from this straightforward concept of “knife”. The radicals’ contribution to character construction can seem reaching in some cases. We will explore these connotations, such as “to cut”, “to separate” and “strong”.


We take a quick look at how indexing radical ‘刀’ (radical 22) got abbreviated to ‘刂’ (radical 8.b).

The “right-throw-hook” stroke (red highlight) on the right gets simplified into a “down-hook” stroke. The “throw” stroke on the left gets packed to the right as a “down” stroke. The proximity of the resultant “down” stroke to the resultant “down-hook” stroke also meant there was no need for a connecting “right” stroke at the top.

Strokes abbreviated. (zdic.net)
Strokes after abbreviation. (zdic.net)

When it means “knife”

The closest connotations to “knife” generally describe “knife” directly, for example, a physical part of “knife” or the “sharp” quality of “knife”.

The character ‘刃’ (ren4, character 48) refers to a physical part of “knife”: the “blade”.

The original form of ‘刃’ has an indicator (red arrow) that points to the “blade” of a “knife”.

Indicator (red) points to “blade”. (baike.baidu.com)

Note that the above “knife” pictorial is horizontally flipped but is clearly similar to the original “knife” pictorial in ‘刀’ (“knife”, dao1, character 18). (The article on character construction strategies explains the character construction for “knife”; section “It only gets easier → Reversing the mutations”.)

“Blade” (red) and crossguard (blue) in early form for “knife”. (zdic.net)

Due to substantial mutation of the original “knife” pictorial, that “blade” indicator no longer clearly points to the “blade”. Today, it may be easier to memorize ‘刃’ (“blade”, ren4) by considering the indicator as a “drop of blood”.

Current form for “blade”. (zdic.net)

The next closest connotation to “knife” is “sharp”.

The character ‘利’ (“sharp”, li4, character 763) features ‘禾’ (“millet”, he2, character 267, radical 111) and ‘刂’ (“knife”, dao1, radical 8.b). An agricultural implement that can be easily used for harvesting, say a scythe, would certainly be “sharp”.

Current form for “sharp”. (zdic.net)

(TODO: Link to character construction for ‘禾’, which is best thought of in combination with ‘木’.)

Because ‘利’ (“sharp”, li4) was originally constructed from the concept of “harvest”, the character’s semantics extended to “profit” (利润, li4 run4) and “benefit” (利益, li4 yi4).

When it means “to cut”

With “knife”, we have the ability “to cut”. Both radicals provide such semantic construction.

In ‘切’ (“to cut”, qie1, character 107), the radical ‘刀’ denotes “cutting”. See the character construction for “seven which relates to that for ‘切’.

Current form for “to cut”. (zdic.net)

In ‘刺’ (“to pierce”, ci4, character 1039), the radical ‘刂’ also denotes “cutting” in a way: “piercing” is another capability for “knife”.

Current form for “to pierce”. (zdic.net)

The improvised radical ‘朿’ (“thorn”, ci4) is an old character for ‘刺’, which has another meaning that is “thorn”. This old character is no longer in use, and is not found in the Table of Characters.

To easily memorize ‘朿’ (“thorn”, ci4), consider its earlier form, which is clearly a thorny structure.

Earlier form for “thorn”. (zdic.net)

The current form can be thought of as a plant ‘木’ (“wood”, mu4, character 87) with “hooked thorns” (red highlight).

“Hooked thorns” on a “plant”. (zdic.net)

(TODO: Link to character construction for ‘木’.)

When it means “to destroy”

Extending from the sense of “to cut”, one of these “knife” radicals can mean “to destroy”.

In ‘剿’ (“to exterminate”, jiao3, character 3048), ‘刂’ (radical 8.b) provides semantic construction for “to destroy”. Since ‘巢’ (chao2, character 2500) means “nest”, ‘剿’ (jiao3) means “to totally and thoroughly destroy”, such as in phrases like ‘剿匪’ (jiao3 fei3, “to exterminate bandits”).

Current form for “to exterminate”. (zdic.net)

(TODO: Link to character construction for ‘巢’.)

When it means “to separate”

These “knife” radicals also semantically indicate “to separate”, a logical semantic extension given that “separating” does require “cutting”.

The character ‘分’ (“to separate”, fen1, character 146) consists of ‘八’ (“eight”, ba1, radical 11) and ‘刀’ (“knife”, radical 22). The original sense of ‘八’ (ba1) was “to separate”, until it was assigned to “eight” and ‘扒’ (“to separate by hand”, character 201) took its place. Since ‘八’ (ba1) now means “eight”, the radical ‘刀’ (“knife”, radical 22) must be added to create the character for “to separate”: ‘分’ (fen1).

Current form for “to separate”. (zdic.net)

A character that features ‘刂’ (radical 8.b) that stands for “to separate” is ‘别’ (“to part”, bie2, character 751). This character is usually used to describe some voluntary parting, such as in words like ‘告别’ (“to bid farewell”, gao4 bie2).

Current form for “to part”. (zdic.net)

The original meaning of ‘另’ (“other”, ling4, character 256) is “to be apart”. The character construction of ‘另’ (“other”, ling4) has a ‘口’ (“mouth”, kou3, character 38) that parts on its own ‘力’ (“strength”, li4, character 19) . The semantic contribution of ‘另’ (“other”, ling4) in ‘别’ (“to part”, bie2) is hence “voluntary parting”.

Another character that features ‘刂’ (radical 8.b) that stands for “to separate”, one for which the semantic contribution is reaching, is ‘剩’ (“remaining”, sheng4, character 2675). Apparently, anything “remaining” seems to have been caused by some prior cutting, such as a cut cake.

Current form for “remaining”. (zdic.net)

The character ‘乘’ (“to ride”, cheng2, character 1941) provides phonetic construction.

(TODO: Link to character construction for ‘乘’.)

“Separated”, but “paired”

A paradoxical semantic switch from “to separate” gave rise to the sense of “to correspond to” (to match, to conform to). This sense describes 2 “separated” entities that then “correspond with” each other.

This semantic switch is seen in ‘副’ (“deputy”, fu4, character 2234). A deputy (an assistant) indeed “corresponds to” his/her superior. The character ‘畐’ (“full”, fu2) provides phonetic construction.

Current form for “deputy” or “to correspond to”. (zdic.net)

The character ‘畐’ (“full”, fu2) is no longer in use, and is not even in the esoteric section (category 3, characters 6501 to 8105) of the Table of Characters. Still, we can easily grasp its construction, to understand its contribution to character construction; it is used today only as a radical.

(TODO: Link to article for radical ‘畐’.)

When it means “strong”

This sense is possibly best viewed as “strong enough to withstand a knife’s cutting”. In reality, blades can be broken and aren’t as strong as, say, a rock.

In ‘刚’ (“firm”, gang1, character 441), ‘冈’ (“ridge”, gang1, character 115) pictorially contributes a “fish net”, and ‘刂’ (radical 8.b) semantically denotes “strength” (that withstands cutting).

Current form for “firm”. (zdic.net)

(TODO: Link to character construction for ‘冈’.)



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