There are many varieties of rice in the world - it is the grain with the highest production for human consumption (if we include non-human consumption such as cattle feed, it would take second place after maize). The rice traditionally eaten in Japan (and the only one suitable for traditional Japanese meals) is called Oryza sativa Japonica. "Oryza sativa" is the rice grown in Asia (different from Oryza glaberrima, the rice grown in Africa). But even among Asian rice there are many varieties - the Indians for example, prefer rice that is dry and doesn't stick too much together ("like two brothers - close but not sticking too much together"), while the Japanese prefer a short-grained subspecies of which the grains stick together like they themselves in their full country. This is thanks to amylopectin, a substance in Japanese-produced rice that gives it a beautiful texture and the slightly glutinous quality that makes the grains stick together.
The traditional method for cultivating rice is to flood the fields after planting the young seedlings, as this reduces the growth of weeds and deters vermin. This requires a high level of organization and cooperation among farmers - in early historical periods, this gave rise to Japanese social organization. In Japan, planting and harvesting is highly mechanized nowadays.
After harvesting, the grains are first treated with a rice huller to remove the chaff (the outer husks of the grain). The result is called "brown rice," genmai. Brown rice lacks the fragrance of hakumai and is mainly sold in organic restaurants and shops. Most Japanese prefer "white rice," hakumai, which is obtained by polishing the rice (removing the other layers of the grain by milling it down). The powder that is removed in this process is called nuka (rice bran). Rice bran is used for many purposes such as the white powder that coats Japanese sweets (wagashi) or for making one type of pickles (nukazuke).
[Young rice plants]
Food rice is milled down to an average of 92% of the grain. Rice as ingredient for other purposes, such as sake making, is milled much further, to 70%, 60%, 50% and even 35% of the original size - this to remove off-flavors in the sake and obtain a purer taste.
A product in between brown rice and white rice is "sprouted brown rice," hatsuga genmai, which has a softer texture than brown rice, yet retains its health benefits. It has been soaked in warm water intil germinated and is also known as GABA riceBut this, too, is only sold in small quantities as white rice rules the day. Haigamai, finally, is rice that has been partially milled to remove most of the bran but leave the germ intact. It therefore retains more vitamins than white rice.
Normally, rice has to be washed before boiling it. Nowadays there is also musenmai on the market, rice which doesn't have to be washed, not because it has been washed before packaging, but because of a new system of polishing the rice whereby no rice bran is left on the rice grains.
White rice is sold milled in supermarkets in plastic bags of 1, 2, 5 or 10 kilograms. In the countryside, one can find coin-operated rice polishing machines, where farmers can polish their own rice for consumption at home. 10 kg of rice are usually polished for 100 yen.
White rice keeps very long (it was not for nothing used as money and to pay taxes in traditional Japan), but lacks certain important nutrients. It must therefore be supplemented with other dishes such as tsukemono.
There are two types of Japonica rice: non-glutinous (called uruchimai) and glutinous (called mochigome). The first one is used for normal cooking, the second one for special purposes such as making rice cakes (mochi), red rice (sekihan), steamed glutinous rice (okowa) and Japanese sweets.
In the last sixty years, many types of improved "rice brands" have been developed in Japan, just as there are different tasting brands of potatoes or grapes. Popular brands are Koshihikari, the most widely planted variety, originally from Niigata Prefecture, popular for its taste. Others are, for example, Akitakomachi (Akita Prefecture; sticky like glutinous rice, very suitable for making onigiri), Sasanishiki (from Miyagi; this variety keeps a good taste also after cooling down, which makes it good for sushi), Hitomebore (from Iwate Prefecture; sweetly fragrant), etc. Most Japanese prefectures have developed their own brands. For the production of high-quality sake, there exist several brands of special "sake rice" which have larger grains and more starch - and these also are "branded," i.e. Yamada Nishiki, Gohyakumangoku, etc.
Japan is the ninth largest rice producer in the world, despite the fact that rice production is presently stagnant and consumption is declining. However, many Japanese see the importance of rice production in conserving their cultural heritage.
In 2015, rice production in Japan was 7.99 million tons. About 85% of the 2.3 million farms in Japan annually plant rice. The average rice field acreage of a Japanese farmer is small (about 0.8 hectares) and rice production is highly mechanized. Due to the small farm sizes, rice production is considered a part-time occupation by most farmers.
The main rice season in northern Japan lasts from May-June to September-October. In central Japan, it is from April-May to August-October. In southern Japan the rice season is from April-May to August-September.