Simmer - ゆっくり煮る
Cover - 蓋をする
Slice onion thinly and cut chicken to bite size pieces.
Put water, mirin, dashi, and sugar in a pan and let the mixture come to a simmer at medium high heat.
Add onion slices and simmer for about 2 minutes.
Add chicken and soy sauce and reduce to medium heat.
Cover and simmer for 3 minutes or until chicken is cooked.
Add the lightly beaten eggs.
Cover and simmer for a minute.
Remove cover and simmer for another minute.
Turn off heat and let it rest for 3 minutes.
Serve over rice in a deep bowl. Add seaweed flakes if desired.