From fish tails ‘丙’ to people ‘人’ in Chinese writing

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Last updated: 28 Feb 2021

This article is part of a compendium of 3500 characters.

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As early Chinese vocabulary and writing system expanded, the development of Chinese written forms encountered collisions, where a single form inadvertently ended up representing disparate concepts.

In witnessing this phenomenon of collision, we are able to easily learn Chinese characters that may otherwise be difficult to extract logical mnemonics from.

The following Chinese characters are related by a common theme: collision avoidance.

Fish tail inside: 丙 and 内

The story of the collisions are circular, but this seems like a good place to start: “fish tail” ‘丙’ (character 213, bing3) and “inside” ‘内’ (character 116, nei4).

(The character ‘丙’ (bing3) no longer means “fish tail” but “third”. More on this later in the section about semantics and word construction.)

The earliest form of ‘丙’ (“third”, originally “fish tail”, bing3) looks extremely similar to ‘内’ (“inside”, nei4).

An early form for ‘丙’, which meant “fish tail” (

At this point, “fish tail” (above) and “inside” (below) didn’t have enough visual difference to be easily written or read. No, you’re not seeing double! But they look almost like twins, right?

An early form for ‘内’, “inside” (

The first differentiating change: the “fish tail”

The first change to “fish tail” (‘丙’, bing3) was in 2 areas:

  • The original “hollow” shape was filled to better resemble a fish tail.
  • The top edge extended to protrude left and right.
    (Possibly a rack to which a fish tail was tied?)
First change: color it in for ‘丙’, “fish tail” (
Fish tail, for real! (

The “coloring” change didn’t take in future evolution, probably because it took too much effort to write (or paint, rather).

The sideways protrusion of the top line (pictorially a rack?) did take, which would become the basis for the progression towards today’s written form for “fish tail” (‘丙’, bing3). We will discuss this progression further below.

It is likely this first change aimed to better resemble a fish tail, rather than to differentiate the early written form from “inside” (‘内’, nei4).

The first differentiating change: the “inside”

The first change for “inside” (‘内’, nei4) involved its flat top; it was sharpened upwards. (Possibly occurring before or concurrently with the first change for “fish tail” ‘丙’, bing3.)

The first differentiating modification for ‘内’, “inside” (

It is highly likely this first change to “inside” (‘内’, nei4) aimed to differentiate the early written form from “fish tail” (‘丙’, bing3), the version without the “coloring in”.

Considering that “coloring in” for written forms quickly became unpopular — the vast majority of early written forms were comprised of strokes — early Chinese could have anticipated that the first change to “fish tail” (‘丙’, bing3) wouldn’t take.

Having discussed the collision avoidance for both characters, we continue with the complete evolutionary paths of both.

Evolution of “fish tail”, ‘丙’ (bing3)

A separate “right” stroke was added as a clearer emphasis than the original longer “right” stroke.

Protruding top “right” stroke was retained, but not the “coloring in”. (

The protruding top “right” stroke would later (below) be emphasized as a separate stroke.

Top stroke added to emphasize a formerly longer stroke. (

The final step of the evolution was possibly part of a standardization and consolidation effort. As “inside” (‘内’, nei4) had by the time evolved into a form where the internal structure pierced upwards through the semi-bounding box (see next section), the consolidation effort could have borrowed that form here.

Current form for “fish tail”, which also means “third”. (

It’s easier to memorize both characters, “fish tail” (‘丙’, bing3) and “inside” (‘内’, nei4) when they differ only by an additional stroke.

This change is unlikely to be a development for faster writing in cursive style. Consider that ‘元’ (“dollar”, yuan2, character 80) retains the top “right” stroke that is separate.

Evolution of “inside”, ‘内’ (nei4)

Precisely aligning the two upward thrusts is obviously difficult. (The example we found from historical records actually is misaligned! See below.)

Not easy to align both upward thrusts. (

Perhaps to remove the need for the above-mentioned alignment, as well as to save on the number of writing strokes, the internal structure was merged with the semi-bounding box. Also, the resultant semi-bounding box became much easier to write, consisting of only straight lines.

Simpler strokes, fewer strokes. (

Without looking at the evolution of “inside” (‘内’, nei4) — which involved collision avoidance with “fish tail” (‘丙’, bing3) — it would have been difficult to extract logical mnemonics to memorize this character. One may have thought “why doesn’t this character mean ‘puncture’ instead”.

Standardization of writing strokes brings us to the current form for “inside” (‘内’, nei4, character 116).

Current form for “inside”, nei4. (

From here, we encounter yet another collision avoidance: between “enter” (‘入’, ru4) and “person” (‘人’, ren2).

Enter person: ‘入’ and ‘人’

The evolution of “person” (‘人’, ren2, character 10) developed separately from “fish tail” (‘丙’, bing3), “inside” (‘内’, nei4) and “enter” (‘入’, ru4). Its current form is simple enough, so we don’t have to look through its long history (which involved people hard at work, hardworking were the Chinese!).

The current form resembles a person in motion, walking.

Current form for “person”, like someone walking. (

Having settled the discussion of “person” (‘人’, ren2), we study the more complex evolution for “enter” (‘入’, ru4, character 11).

An early form of “enter” (‘入’, ru4) actually looks like “person” (‘人’, ren2).

Early Han form for “enter”, ‘入’, ru4. (

Evolution of “enter”, ‘入’

This early form for “enter” (‘入’, ru4, character 11) was likely extracted verbatim from the early form for “inside” (‘内’, nei4).

Early source of “enter” (‘入’, ru4) from early form of “inside” (‘内’, nei4) (

The mnemonics is obvious: the structure that enters into the semi-bounding box seen in “inside” (‘内’, nei4) would naturally stand for “enter”.

Collision avoidance for “enter”, ‘入’

Even before the standardization and consolidation into final form, the Han form had changed (forms 15 and 16) to avoid collision with “person” (‘人’, ren2).

The current form for “enter” (‘入’, ru4) is written with a shorter “throw” stroke, whereas “person” (‘人’, ren2) has a longer “throw” stroke.

Current form for “enter” (‘入’, ru4). (

Semantics and Word Construction

The contemporary semantics for all four characters — “fish tail” (‘丙’, bing3), “inside” (‘内’, nei4), “enter” (‘入’, ru4) and “person” (‘人’, ren2) — are all straightforward. They aren’t overloaded with multiple meanings.

The only character of note here is “fish tail” (‘丙’, bing3) which, along with the advent of an ancient Chinese ordinal system, also symbolically means “third”.

We’ve completed the extraction of useful mnemonics for “fish tail” (‘丙’, bing3), “inside” (‘内’, nei4), “enter” (‘入’, ru4) and “person” (‘人’, ren2). The extraction method is mostly based on pictorial construction, but is necessarily coupled with collision avoidance in the evolution of written forms where pictorial construction couldn’t apply.



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