Dissolve the yeast in 1/2 cups warm water. Let stand until bubbles appear on the surface.
Add 1 cup warm water, 200g flour, sugar, salt. Mix ingredients. Cover with a clean cloth and let rise until doubled in volume.
Then add more flour and mix again (add more flour that the batter should be sticky). Cover again, and let rise until doubled.
Preheat oven to 392 degrees F (200 degrees C).
Spoon the mixture into a lightly greased and floured loaf pan. Cover again, and let rise until doubled. Sprinkled with black sesame seeds if desired.
Bake for about 45 minutes.
Place on a cooling rack.
Enjoy!