# mace

> former Chinese coin named for a traditional Chinese unit of mass, about 3.78 g

**Wikidata**: [Q108913757](https://www.wikidata.org/wiki/Q108913757)  
**Source**: https://4ort.xyz/entity/mace

## Summary
The mace is a former Chinese coin named for a traditional Chinese unit of mass, weighing approximately 3.78 grams. It functions simultaneously as a historical unit of currency and a unit of measurement for mass, rooted in traditional Chinese metrology.

## Key Facts
- **Definition**: A former Chinese coin named for a traditional Chinese unit of mass, about 3.78 g (Wikidata description).
- **Aliases**: Chinese qian, Chinese mace, qián, 钱.
- **Mass Conversion**: Converts to 0.00378 kilograms in the SI unit system.
- **Classification**: Instance of `unit of mass`, `cash` (currency type), and `currency`.
- **Hierarchy**: Part of `Chinese unit of measurement` and `Chinese currency`.
- **Subdivision**: The unit `cash` is defined as a subdivision of the mace.
- **Physical Quantity**: Measures `mass`.
- **Digital Code**: Represented in Wolfram Language by the unit code "ChineseQians".
- **Parent Class Context**: Currency (parent class) is generally accepted medium of exchange for goods or services, documented in 166 Wikipedia languages.

## FAQs

**What exactly is a mace in Chinese history?**
A mace (qián or 钱) is a traditional Chinese unit of mass that was also used as the basis for a historical coin. It weighs approximately 3.78 grams (0.00378 kg) and served as both a weight standard and a form of currency in imperial China.

**How does the mace relate to other Chinese units?**
The mace is part of the broader systems of Chinese units of measurement and Chinese currency. Specifically, the unit known as "cash" represents a subdivision of the mace, indicating its role as a higher-order denomination in the traditional measurement and monetary hierarchy.

**Is the mace still used today?**
While the mace is classified as a former Chinese coin and historical unit, it is encoded in modern computational systems—specifically, the Wolfram Language includes it under the unit code "ChineseQians," allowing for digital conversion and reference.

## Why It Matters
The mace is a tangible intersection of Chinese metrology, economics, and material culture. As a unit that was simultaneously a mass measurement and a coin, it demonstrates how pre-modern economies often conflated weight and value, tying currency directly to physical substance rather than abstract fiat. Its persistence in databases like Wikidata and computational platforms like Wolfram Language underscores the importance of preserving historical units for accurate interpretation of Chinese historical texts, trade records, archaeological artifacts, and numismatic collections. Furthermore, as a component of the larger Chinese currency and measurement systems, it provides essential context for understanding the scale and structure of commerce in one of the world's oldest continuous civilizations.

## Notable For
- **Dual Identity**: Uniquely serves as both a unit of mass and a historical coin, bridging metrology and numismatics.
- **SI Conversion**: Has a precisely defined SI conversion factor (0.00378 kg), anchoring a traditional unit to the modern metric system.
- **Computational Presence**: Maintains a dedicated unit code ("ChineseQians") in Wolfram Language, ensuring its utility in modern technical computing.
- **Hierarchical Role**: Functions as a parent unit to the "cash," a widely recognized subunit in traditional Chinese monetary systems.
- **Linguistic Breadth**: Known by multiple names including Chinese qian, Chinese mace, qián, and 钱, reflecting its cross-cultural and historical usage.

## Body

### Core Definition and Physical Properties
The entity "mace" is a former Chinese coin named for a traditional Chinese unit of mass. According to its Wikidata description, it is defined by this dual nature as both a physical denomination and a unit of weight. It is classified as an instance of three distinct concepts: `unit of mass`, `cash`, and `currency`. The measured physical quantity associated with the mace is `mass`. In terms of modern standardization, the mace converts to the SI base unit of kilograms with an exact amount of 0.00378 kg.

### System Membership and Context
The mace is structurally embedded in two major traditional Chinese systems. It is listed as `part_of` the `Chinese unit of measurement`, placing it alongside other historical units of length, volume, and weight. Simultaneously, it is `part_of` `Chinese currency`, situating it within the long history of Chinese monetary instruments. The relationship between the mace and smaller denominations is explicitly defined: the `cash` is a `subdivision_of_this_unit`.

### Nomenclature and Aliases
The mace is known by several names that reflect its Chinese origin and its phonetic translation. Its primary aliases include:
- Chinese qian
- Chinese mace
- qián
- 钱

### Digital and Computational Representation
Despite its status as a historical unit, the mace has been integrated into modern computational frameworks. It possesses a specific `wolfram_language_unit_code` identified as "ChineseQians." This allows the unit to be used programmatically for unit conversions, calculations, and data analysis within the Wolfram technical computing environment.

### Relationship to the Parent Class "Currency"
As an instance of `currency`, the mace exists within the broader conceptual framework of generally accepted mediums of exchange for goods and services. The parent class "currency" is a foundational economic concept documented extensively across global knowledge systems, including 166 Wikipedia language editions. It is classified as a subclass of `medium of exchange`, `unit of measurement`, `money`, and `means of payment`. The concept of currency is distinguished from related but separate items such as `money` (the broader category), `coin` (a physical form), and `foreign currencies` (a subset). It is anchored by model examples including the `United States dollar`, `euro`, `Indian rupee`, and `Icelandic króna`, and is represented in digital systems by the Unicode character `💵` and OpenStreetMap key `currency`. This high-level classification context validates the mace's position as a recognized, albeit historical, monetary unit in global knowledge bases.