There are many kinds of udon tastes such as the difference from soup taste and the thickness of noodles etc. Hanamaru Udon is a udon restaurant chain founded in Takamatsu. It has more than 450 restaurants in Japan as of 2018. You can find the restaurants and eat udon there while traveling in Japan.
Hanamaru : https://www.hanamaruudon.com/company_outline/company1.html
In the pictures, first one is Kamatama udon which is mixed with raw egg soon after the noodle is boiled. Second one is Ontama udon with beef and two tempura.