Most chefs cook Sushi rice with a rice cooker. It is easy, and requires less attention to the cooking process. However, there are still some chefs that prefer the traditional method of cooking Sushi rice.
How to cook Sushi Rice in kama (Japanese Stove)
The old school Sushi chefs use an old fashion Japanese stove or kama and use a iron pot to cook the rice. The heat distribution of an iron pot is just about perfect for Japanese rice, but it requires stronger heat. This is fulfilled by the kama. This makes the rice cook evenly, and have a fluffier result.
After the rice is washed to get rid of extra talc, fresh spring water is added and a piece of binchotanor (water insoluble Japanese charcoal) is added before the wooden lid is placed.The charcoal will get rid of any impurities in taste while it is cooking the rice, and lighten the flavor as much as possible.
Some chefs may throw in apiece of kombu to flavor the rice, and not include it in their sushi rice vinegar.
Once it is cooked, the pot is taken off the stove and a handful of clean wara (hay) is placed in the pot and closed again to soak out extra moisture. It takes a frequent rice consumer to know the difference, but these intricate details are characteristics of true sushi chefs.