Japanese udon can be round square or flat with a texture suitable for more hearty dishes they are made from wheat salt and water although udon can be served cold these thicker soft but slightly chewy white are usually served hot with various toppings added to a hotpot dish and cooked with other ingredients or sometimes included in a curry soup udon can replace soba in traditional soba recipes and some dishes even mix soba and udon to give a variety of textures