Warm the teapot with hot water, then discard it. Add the green tea and pour in about 1/2 cup hot water. Swirl for 10 seconds and discard the liquid, keeping the leaves.
Add the remaining hot water, mint, and sugar. Let steep for 5 minutes.
Mix and Serve:
Stir the tea gently with a long spoon. Pour one glass, then return it to the pot to mix the stronger tea from the bottom with the lighter tea above.
Pour again from a little height into small glasses with mint sprigs. Serve hot.
Notes
Rinsing the tea leaves helps reduce bitterness.
Spearmint gives the most traditional aroma.
Pouring back one glass mixes the pot evenly before serving.