Jin (斤 — jīn) is the traditional Chinese unit of weight. It is kept in pinyin throughout this site rather than rendered as “catty”, and its mass is not one figure but several, because successive dynasties reset it.
Why not catty
“Catty” is not an English rendering of a Chinese word. It came into English from the Malay kati, meaning “the weight”, carried by the East India Company and the treaty-port trade — the same road that brought tael, from tahil, and the same root that gave English caddy, as in the tea caddy.
These are the words of the people weighing the cargo. They were standardised at the treaty ports so that foreign merchants and foreign customs houses could quantify Chinese goods for export, not derived from anything a person in the story would have said. To write “four hundred catties” is to describe a Song strongman’s feat in the idiom of a nineteenth-century bill of lading.
The objection is not that the words are offensive, and capable translators have used them in good faith. It is that a unit of weight is ordinary, high-frequency detail, and detail of that kind either sustains the reader’s place inside the world or quietly undoes it. There is a grammatical tell, too: catty, tael and picul are the only Chinese measures that take an English plural, because they are the only ones English fully absorbed. See Liang for the fuller argument.
Why the figure changes between novels
The jin’s ratio to the units around it held remarkably steady — sixteen liang to the jin for most of imperial history, which is the arithmetic behind 半斤八两, “half a jin and eight liang”, for two things not worth telling apart. Its absolute mass did not.
This matters for reading rather than for pedantry. When a character lifts a four-hundred-jin cauldron or a blade is said to weigh seventy jin, the figure is telling you what counts as a feat in that world. Converting with the modern value flattens it, because the modern jin is the lightest the unit has ever been.
| Setting | Approximate mass | Novels |
|---|---|---|
| Song | 640 g | Legend of the Condor Heroes, Return of the Condor Heroes, Demi-Gods & Semi-Devils |
| Yuan | 640 g | The Heavenly Sword & the Dragon Sabre |
| Ming | 590 g | — |
| Late Qing | 596.8 g | Twin Blades of the Storm Dragon, Mandarin Duck Blades |
| Modern (市斤) | 500 g | Standardised to half a kilogram in the twentieth century |
The Song figure is the least settled of these and sources disagree, with estimates from roughly 600 to 640 grams. The higher value is adopted here as the one most commonly cited from excavated Song weights, and because it makes sense of the Ming reduction to 590.
Novels with no fixed era
Some novels decline to place themselves in history. Where an author does that, there is no historical answer to recover — so these take the jin of the author’s own time and place.
That is not a fallback. When an author writes 四百斤, their own sense of how heavy that is comes from the jin they actually know, which makes publication-era arguably the more faithful reading rather than the less. Place matters as much as date: Hong Kong is 604.79 g, Taiwan 600 g, the mainland 500 g.
For the Hong Kong and Taiwan wuxia canon this lands at roughly 600 grams — and that figure is the Qing standard, retained in both places where the mainland decimalised. So the era-agnostic novels and the Qing-set ones agree, and the table stays coherent instead of carrying an outlier.
Related units
- Liang (两) — one-sixteenth of a jin
- Qian (钱) — one-tenth of a liang
- Dan (石 or 担) — a picul, conventionally one hundred jin
See also
- Li — the traditional unit of distance
- Shichen — the traditional two-hour division of the day
External links
- Jin (mass) on Wikipedia
Follow the archive routes
- Read: Browse the translation archive for novels that use traditional units in context.
- Explore: Continue with the Jin Yong reference guide for works, characters, factions, and historical context.
- Understand: Read wuxia for the genre’s relationship with history, language, and material culture.
- Watch: Follow wuxia adaptations from source novels to screen versions.
- Write: Study story elements in wuxia fiction for grounded setting and world-building detail.