CHAC learning mechanics

How CHAC explains a character

A Chinese character can have three different learning jobs: how it is used, how its pieces work today, and how its shape or word developed historically. CHAC keeps those layers separate so a practical explanation, a useful memory aid and the historical record do not blur into one misleading story.

Three layers, three jobs

The Pattern Scroll shows what a sentence tool does

Some characters cannot be understood from an isolated English label. CHAC audited all 327 current cards and identified 80 particles, measure words, question builders, localizers, aspect markers, modal verbs and other structural characters that need a practical pattern. Their Character Scroll shows one compact Sentence Tool row so the memory image and character structure remain the main lesson.

Tapping that row opens a separate Pattern Scroll with one plain explanation, a visual formula, three short examples and relevant comparisons. For example, 第 goes before a number to mark its position in an order, while 条 counts long, narrow or winding things.

Each Pattern Scroll also opens a small Sentence Forge exercise. The learner puts the example characters into order and can practise all three examples. This reference practice gives feedback inside the screen but does not grade character mastery or change lesson progression.

The visible breakdown teaches the character as written today

When a character can be divided honestly, CHAC shows every visible component and labels the job each one does: one piece may provide a meaning category, another may provide the base sound, and a piece that provides neither is labelled a shape rather than given an invented meaning. CHAC preserves exact, source-supported modern visual pieces even when history no longer matches them, and uses the historical explanation as the backup. If a current block cannot be split further but has a reliable historical identity, CHAC can show that whole block as one shape and explain its older origin in the component note. It does not replace an exact block with unsupported visual fragments. Where a piece supplies the sound, CHAC prints both readings and says which of three things happened: they still match, only the tone moved, or the two have drifted apart over the centuries. It never says a component "lends its sound" and leaves it there.

The breakdown stays to the pieces and their labels, so the character and its picture remain the main lesson. Tapping a piece is what names it. A small popup gives that component's meaning and can open a read-only character scroll when the component is taught as its own character, a focused component scroll when it is not, or a local-detail scroll when the shape belongs only to the parent. Reference components explain their attested historical origin and their job inside the parent character. Local details explain only the exact written shape and its place in the parent. Every route returns to that exact parent without changing lesson progress or mastery.

The question mark adds attested history

The expandable explanation does not repeat the breakdown. It adds an older written form, a change in meaning, simplification history, word history, or the genuine relationship between two meaning components.

What that looks like

人

A pictogram

人 has no useful modern component split. Its question-mark explanation therefore carries the main history: the oldest form drew a person from the side, with a body, arm and striding leg.

爸

A meaning-plus-sound compound

The visible breakdown marks 父 as the meaning part and 巴 as the base sound, bā, sitting directly under the character's own pronunciation, bà. Tapping 父 names it as father. The question mark then goes further: 爸 developed as the familiar spoken word for dad alongside the older word 父.

出

A shape we refuse to fake

出 can look like two copies of 山, but that is not its historical construction. CHAC shows the exact current visible shapes as shape-only pieces, without claiming they mean mountain. Its oldest form showed a foot leaving a cave or enclosure, and that historical explanation remains separate from the modern shape breakdown.

How the picture helps you remember the shape

Whenever it remains natural and historically honest, CHAC uses the modern character as the picture's composition grid. A person may stand along the strokes of 人, or two historical objects may hang in the same side-by-side arrangement as the character they became. Red brushwork connects or clarifies the shape instead of simply placing a large character over an unrelated scene.

The rule is flexible. If literal alignment would create an awkward picture, hide the important symbol or suggest a false origin, the picture uses a looser resemblance. The historical idea and a clear memory cue matter more than forcing every stroke into an object.

In the app's Profile settings, you can independently turn character breakdowns, visual memory cues, form families, historical notes and Sentence Tool shortcuts on or off. All five are on by default. Turning off visual cues hides only the artwork, while turning off the other aids hides their optional sections without changing the character's pronunciation, meaning, lesson or mastery behavior.

Radicals, components, and compact forms

These terms are often treated as though they mean the same thing. They do not. CHAC focuses on components because components explain how a character works, while a radical is mainly a dictionary classification.

Character: The complete written unit, such as 你.
Component: Any visible building piece inside a character. 亻 and 尔 are the two components in 你.
Radical 部首 (bùshǒu): The one component chosen to place a character in a traditional dictionary section. It often suggests a meaning category, but not every component is the radical.
Sound component: A component that supplies a historical pronunciation clue. Its modern sound or tone may have changed.
Shape only: A piece that supplies neither meaning nor sound in the character as written today. Simplification is the usual reason: 欢 now writes 又 where the older form carried a sound component. CHAC labels the piece a shape and explains why, instead of teaching a meaning it does not have.

人亻尔你

One known character can change shape inside another

人, pronounced rén, is taught as the standalone character for person. When it stands on the left of another character, it compresses into 亻. In 你, this compact person form provides the meaning category. 尔, pronounced ěr, provides the historical sound clue, while 你 is pronounced nǐ today.

CHAC connects a compact form to its complete historical character, such as 亻 to 人, 扌 to 手, and 氵 to 水. A taught full form opens its complete character scroll. An untaught full form opens a focused component scroll headed by the full character, with the compact form shown directly beneath it. The compact shape remains reference material, not a separate vocabulary card.

Why some written pieces open a deeper explanation

CHAC does not treat every visible stroke as a tiny character with its own lesson. A tap opens a further scroll only when there is a useful, reliable explanation to give. The app keeps the distinction quiet, but it follows three routes:

Reference component: A complete, identifiable piece with its own sourced explanation. It can open a character or component scroll. Its own usual meaning does not automatically become the meaning of the larger character.
Compact form: A positional version of a complete character, such as 亻 from 人. Some positional forms keep the same Unicode character but use a native slot outline, such as the left-side 土 in 场 or the right-side 夬 in 块. It opens the reference for the full form rather than pretending the compact shape is separate vocabulary.
Local detail: An exact stroke or shape needed to write the larger character today, but with no honest standalone meaning or origin to teach. When it contributes neither meaning nor sound, CHAC labels it shape and opens a focused local-detail scroll that describes only its place in the parent instead of inventing a meaning or history for it.

For example, 候 contains the compact person form 亻, which leads to 人. Its extra vertical, turning and horizontal strokes are labelled shape because they are part of the modern written form, not separate components to learn. Tapping one opens a local-detail scroll that explains that exact stroke in 候. The visible 矢 can still open a reference explanation, while the breakdown makes clear that it does not make 候 mean arrow.

How each explanation is chosen

Research the attested origin in oracle bone, bronze, seal-script and historical dictionary records.
Classify the character: pictogram, indicative symbol, meaning combination, meaning-plus-sound compound, phonetic loan, or a modern simplified form.
Add a visible breakdown only when it accounts honestly for the complete modern character.
Write the question-mark explanation from the historical record, adding information the visible breakdown does not already teach.
Record the origin, the in-app wording and the supporting links in CHAC's research ledger.

CHAC currently has one research record for every character it teaches. All 327 current records are marked historical. Its 146 untaught component targets also have a checked origin record, and every compact-to-full link is covered by the app's build guard. If no reliable origin can be found in the future, an original mnemonic must be labelled invented rather than presented as history.

Sources

CHAC checks each character separately. These are the main public references behind the research ledger:

Unicode Standard Annex #38: radical-stroke counts, the official Unicode description of how Han characters are indexed by a selected radical and their remaining strokes.
Princeton University: radicals and components of characters, a beginner overview of common radicals and character structures.
Outlier Linguistics: Getting Radical About Radicals, a detailed explanation of why functional meaning and sound components are more useful for learning than treating every piece as a radical.
Wiktionary: 人, glyph origin, an example of the glyph-origin entries used for oracle bone, bronze and seal forms.
Wiktionary: 爸 and Wiktionary: 父, glyph origin, sources behind the dad example above.
Wiktionary: 媽, glyph origin and etymology, the traditional form researched for simplified 妈.
Chinese Text Project: Shuowen Jiezi, a searchable edition of the early Chinese character dictionary.
Oracle bone script overview, background on the earliest substantial body of Chinese writing.

Historical character analysis can be debated. When trustworthy sources disagree, CHAC records that uncertainty instead of presenting one theory as settled fact.