Convert japanese koku to imperial gallons in seconds
1 石 x 39.68 = 39.68 imp gal
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Ever wondered how much rice it took to feed a samurai? Or maybe you're restoring a 17th-century sake recipe that calls for "three koku" of water? Whatever brings you here, converting between Japan's traditional koku and Imperial gallons isn't just about numbers – it's a journey through samurai economics and British measurement history. Let's crack this nut with some modern tools and historical flair.
Units explained
What is a japanese koku (石)?
The koku (pronounced "koh-koo") was more than a measurement – it was the economic heartbeat of feudal Japan. Originally defined as enough rice to feed one person for a year (about 180 liters), it became the standard for land valuation. Samurai received stipends in koku, and daimyo lords boasted about their koku yields like modern CEOs flaunt revenue.
- Symbol: 石
- Common uses: Rice production, land valuation, sake brewing
- Modern definition: 1 koku = 180.39 liters = ~39.68 Imperial gallons
What is an imperial gallon (imp gal)?
Born from Britain's 1824 Weights and Measures Act, the Imperial gallon was designed to standardize volumes across the empire. While most countries have switched to liters, you'll still find Imperial gallons used for beer and cider in UK pubs, and for fuel economy ratings in Canada.
- Symbol: imp gal
- Common uses: Liquid volumes in Commonwealth countries
- Definition: 1 Imperial gallon = 4.54609 liters
Conversion formula
The magic equation connecting these historical heavyweights:
Imperial gallons = Koku × 39.68
or
Koku = Imperial gallons ÷ 39.68
Why 39.68? It comes from: 1 koku (180.39 L) ÷ 4.54609 L per Imperial gallon = 39.6833...
Example calculations
- Converting 2.5 koku to Imperial gallons
2.5 × 39.68 = 99.2 Imperial gallons
That's enough to fill about 198 standard UK pint glasses! - Turning 150 Imperial gallons back to koku
150 ÷ 39.68 ≈ 3.78 koku
Roughly the annual rice ration for four Edo-period farmers.
Conversion tables
Koku to imperial gallons
| Koku | Imperial gallons |
|---|---|
| 1 | 39.68 |
| 2 | 79.36 |
| 5 | 198.40 |
| 10 | 396.80 |
| 20 | 793.60 |
| 50 | 1,984.00 |
Imperial gallons to koku
| Imperial gallons | Koku |
|---|---|
| 40 | 1.01 |
| 80 | 2.02 |
| 200 | 5.04 |
| 400 | 10.08 |
| 800 | 20.16 |
| 2,000 | 50.40 |
Historical background
The koku system began during teh Kamakura period (aprox. 1185-1333), when rice was literally currency. By the Edo era (1603-1868), every domain's wealth was measured in koku. The smallest samurai received about 100 koku annually, while the powerful Maeda clan boasted over 1 million! Meanwhile, Britain was standardizing its gallons to prevent tax disputes over ale and grain measurements. Both units tell stories of empires built on agricultural wealth.
Interesting facts
- Samurai salaries: A mid-ranking samurai's 100-koku stipend equates to 3,968 Imperial gallons of rice annually – about 11 gallons per day!
- Castle stores: Osaka Castle's legendary rice warehouses could hold 110,000 koku – that's 4.36 million Imperial gallons!
- Sake connection: One koku of water (39.68 Imperial gallons) remains a key measurement in traditional sake production.
- Car comparisons: A Toyota Corolla's 50L fuel tank holds about 11 Imperial gallons – just 0.28 koku.
- Global cousins: The koku is similar to Western dry measures – 1 koku ≈ 5.12 US bushels.
FAQ
Koku represented rice yields, which were teh basis of feudal economics. A daimyo's status depended on how many koku his lands produced annually.
Yes! The UK, Canada, and some Caribbean nations use Imperial gallons for fuel efficiency ratings and beverage measurements.
Modern conversions use 1 koku = 39.68 Imperial gallons, but historical values sometimes varied by region in Japan.
Absolutely. Traditional sake recipes still reference koku, though most modern producers use metric measurements.
Imperial gallons are 20% larger. 1 Imperial gallon equals 1.20095 US gallons – crucial for accurate conversions!