The rice sticks together better when it's not chilled, so don't make it too far in advance of serving.
Bring rice and water to a boil in a medium saucepan. Cover, reduce heat, and simmer 15 minutes. Remove from heat; let stand, covered, 15 minutes.
Place rice in a large bowl, and gently stir in rice vinegar with a spoon until combined. Cover rice mixture, and let rest 30 minutes.
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