Japan is a volcanic and mountainous country, with few plains and therefore limited possibilities to develop its agriculture. Only 12% of the land surface is cultivated (compared to 36% in France), and more than half is dedicated to rice cultivation. This appeared during the Jomon period (16,500 - 3000 BC) and it will fundamentally structure Japanese society. Over the centuries, the population will gather on these arable lands, organizing mutual aid for crops, the establishment of irrigation systems and protection against natural disasters.
In this context of agricultural community, rice gradually became a true unit of measurement synonymous with money and power. In feudal Japan, it was used to measure the influence of the Daimiyo (lords), and the rice "goku" became the standard for expressing territorial importance, a goku corresponding to 180 liters. Let's quote as an example the territory of the Kaga region: it became one of the most important zones of influence in Japan to arrive, in the Edo period (~1867) to "Hyakuman goku", that is to say that it represented one million Goku! In other words, Kaga was able to produce 180 million liters of rice per year, a considerable influence! By controlling the rice, the Daimyo reigned over the inhabitants and its territory. More rice simply meant more subjects. Moreover, the control of these vast territories required the help of many Samurai. Employed by the Daimyo, they were paid... in rice!
Of course, this era is over, the land has been reorganized and the Japanese territory has been shaped into 47 administrative prefectures. Rice is therefore no longer used as a unit of measurement. No longer used... except in the sake world where goku is still used; it is used to express the size of a brewery. Just to give a scale of size, a large producer is capable of producing 250,000 goku, or 45 million liters of sake per year, while a small producer can produce around 500 goku, or 90,000 liters. A considerable difference in scale!
Fortunately, in a world as refined as that of sake, rice is not just a simple unit of measurement, and the importance of quality is quickly apparent. For it is the quality of rice that has made the reputation and fortune of certain regions of Japan. Logically, these areas have given rise to strong traditions of sake production, with brewers developing their own methods in situ, with the idea of producing the best sake from local rice. This centuries-long development work, comparable to a research project, has led to the establishment of real currents of thought applied to sake production. Each region has developed its own knowledge, training generations of specialists who have passed on their methods to the present day. There are about ten very influential schools today, including the Echigo Tojo or Nambu Toji schools, for example. The notion of sake terroir is not simply a geographical data linked to the place where the rice is grown, it is also intellectual, intimately linked to the origin of each producer's know-how. In a modern context where people (and rice...) travel very well, it is easy to understand that a sake can be the result of a double influence where a physical and a "virtual terroir" are superimposed.
One important thing to note: the rice used in sake production is quite different from the rice used for everyday consumption. Called Shuzo koutekimai, it is larger, richer in starch and above all resilient after cooking compared to Hanmai, the rice for consumption. These seemingly relatively simple characteristics place great stress on farmers, and the simple fact that the grain is larger means that the ear that carries it is taller, and therefore more sensitive to climatic conditions, particularly winds and typhoons which are frequent in summer and autumn (the period when the ear is the most loaded). The large size of these spikes also affects crop yields. Low yields, risk of loss, and therefore higher production costs make sake rice more expensive than table rice. The impact on the price of a bottle is obvious.
This was not always the case, but today, the jobs of rice farmer and sake producer are well separated. The sake farmer, Kuramoto, buys rice from the farmer, and the farmer has to plan his crops from one year to the next because bookings are made many months in advance, especially for the most sought-after strains. Not all rice is the same, and in rice grown specifically for sake production (5% vs. 95% for consumables rice), only 1% is destined for premium sake production. Considering that within this meager percentage, some rice are considered as references, one can imagine the competition that can exist between breweries to obtain the best qualities. Take the supreme example of Yamadanishiki rice. It is considered to be the king of sake rice. Ultra-reputed, it is one of the preferred rices for the production of daïginjo. Indeed, the grain is coarse and resists well to polishing, which makes it possible to reach high degrees. Its heart, Shimpaku, is very concentrated in starch and the combinations with yeasts are very well mastered. Yamadanishiki is used to make refined sake of stable quality year after year. Brewers therefore do not hesitate to buy this very expensive rice from the best producers, choosing the best grade (A+, compared to B or C grades for less prestigious sake). This is the price to pay to enter a daïginjo in national competitions and demonstrate its technical capabilities; the idea being, of course, to promote the entire brewery. The criteria for being classified as Shuzo koutekimai, or sake rice, are very strict; height, weight, starch concentration, all parameters measured by decision-makers. But there is some overlap with Hanmai, and some drinking rice can be used for sake making. Moreover, producing a remarkable sake with a more common rice is a real challenge that many producers like to take up, with the same respect for this source of wealth, and in the belief that all Japanese will confirm: in a single grain of rice, there are seven gods slumbering.