Sushi rice is very easy and quick to make if you have a rice cooker. All you need to do is: wash the rice in several rinses of water, cook it in the rice cooker (using the sushi setting if you have one), and then toss a vinegar marinade with the rice.
In the top picture there is, clockwise from top: a wooden sushi tub (sushi-oke, used for tossing the sushi rice with rice vinegar and keeping it warm and moist when it is covered with a lid or towel), sushi tub lid, rice paddle, rice (akitakomachi, which is a type of koshihikari, a short grained Japanese rice grown in Japan), sugar, salt, and rice vinegar (jun komezu, which has a golden color because it is pure rice vinegar). The bottom picture has prepared sushi rice.
The single most important thing to have is a short grain Japanese style rice either grown in Japan or in California and to make sure you cook it correctly (I don't cook it stovetop; I use a rice cooker with fuzzy logic since that's what is easiest for me and I already own one). If you can't find jun komezu that's fine, your sushi rice might be a bit less flavorful but it will still taste nice--just find a rice vinegar whose only ingredients are vinegar and water (no sugar or salt because that indicates it is a prepared sushi vinegar dressing and you don't need this since you can make your own). You don't have to own a sushi tub; just make do with a container you have.
The sushi tub should be soaked in cold water while the rice is cooking (about 30 minutes of soaking); otherwise the rice will stick to the dry wood and the wood will absorb a lot of the vinegar dressing instead of the rice. Drain and dry the sushi tub before tossing the rice in it. You don't need to own a sushi tub to make sushi rice; Hiroko Shimbo says that the best substitute is a wooden salad bowl (don't soak it though because that will cause it to crack). I only recently bought my sushi tub since I want to get more serious about my sushi; before that I was using a large rectangular pyrex baking pan because it was flat and large enough for me to toss the rice. Sushi tubs are expensive (around $90 if they are important from Japan), so if you are just getting started learning to make sushi or only plan to make it occasionally, I recommend making do with something that you already own; it's possible for other containers to make sushi rice slightly mushy, but I didn't have that problem with the small quantities I was making in the pyrex baking dish.
For sushi dressing, I use the following proportions suggested by Hiroko Shimbo in "The Sushi Experience". The sushi vinegar dressing quantities are proportional to the amount of rice (though I think she has slightly rounded the amounts for these quantities so that they can be measured with standard kitchen measurement tools), so you can scale these accordingly to the amount of rice you are making. 3 to 4 cups of cooked sushi rice (made from 1 1/2 rice cooker cups of raw rice and 2 rice cooker cups raw rice respectively) is the amount you need for a meal for two people. We can easily finish 3 cups of sushi rice, so this is the amount I make when there are lots of other dishes, fish, etc that will mostly fill us up. I make 4 cups of sushi rice, when there are only a small number dishes, or I'm just serving sashimi or something like that; if the dishes are small than we can finish the full 4 cups, but if there is too much food, then sometimes there will be left over rice.
"Sushi Vinegar Dressing" from "The Sushi Experience" by Hiroko Shimbo
raw Japanese short grain rice *
rice vinegar **
wooden sushi tub (sushi-oke), or substitute a large bowl, preferably wooden
rice paddle, or a broad flat spatula
If you are using a sushi tub, fill it with cold water and allow it to soak for about 30 minutes while the rice is cooking.
Wash rice in several changes of water until the water is nearly clear. Add the amount of water that your rice cooker suggests for the amount of rice that you are making. Since I use a fuzzy logic rice cooker and I like my sushi rice to have a firmer bite, I don't soak my rice for 30 minutes before cooking it (sushi rice is often soaked for 30 minutes if it is cooked on a stovetop). Cook rice in your rice cooker, using the sushi setting if you have one.
While the rice is cooking, mix the rice vinegar with the following proportions:
- 1.5 rice cooker cups makes 3 cups of lightly packed cooked rice, and should be dressed with 2.5 Tbsp rice vinegar (komezu), 3/4 tsp sea salt, and 1 Tbsp sugar
- 2 rice cooker cups makes 4 cups of lightly packed cooked rice, and should be dressed with 3 Tbsp rice vinegar (komezu), 1 tsp sea salt, and 1.5 Tbsp sugar
Once the sushi rice is made, it should be kept covered by a kitchen towel or in a covered container so that it doesn't dry out. It shouldn't be refrigerated, since this will dry out the rice. Since the vinegar is a preservative, the rice will last for about a day at room temperature.
* Use a short grained Japanese-style rice (koshihikari or sasanishiki) grown in Japan or California. Koshihikari has many subtypes, including hitomebore, akitakomachi, hae-nuki, hi-no-hikari, kirara, tama-nishiki, kagayaki, tamaki-mai, and hitomebore. I use either a akitakomachi grown in Japan or "Tamaki Gold" brand koshihikari rice grown in California.
** For rice vinegar, she recommends that you buy one labeled "jun-komezu" (pure rice vinegar). It should have a golden color, and should be made only from rice and possibly water. Do use ordinary komezu for sushi rice, which is made from a combination of rice and other grains (i.e. it is a mixture of rice and grain vinegar); jun-komezu has a richer flavor and aroma. It is okay to use grain vinegar for rinsing and curing fish, and moistening the chef's hands. Also don't buy sushizu, which is a ready made sushi dressing that has vinegar, sugar, and salt; you can easily mix your own, and mixing your own allows you to use the amount of sugar and salt you like.