Add water and powdered kanten into a pot and mix well.
Turn on the heat and continue mixing until it boils over low heat. Continue to heat for 1 more minute after it boils.
Turn off the heat, and add the matcha powder and sugar and mix until they melt.
Turn the heat back on again and continue heating over low heat for more 2 minutes after it boils. Turn of the heat and let it cool down.
Pour the liquid into a shallow flat container and let it harden in room temperature. Move the container into the fridge to cool more.