Clean the chard: remove the coarse outer leaves and cut off the ends of the stems. Wash the leaves thoroughly and drain well in a colander. Cut the stems out of the leaves in a wedge shape.
Cut stems and leaves separately into strips crosswise.
Score the tomatoes on the round side, briefly scald in boiling water, rinse and peel. Then quarter, core and finely dice the tomatoes.
Leave the butter in a pan, sauté the chard stalks with the onion and garlic cubes for 4 minutes. Season with a good pinch of sugar and stir in the teriyaki sauce. Add the leaves and sauté briefly for 2 minutes. Finally fold in the coriander greens and the tomato pieces and heat briefly.