Heat <quantity>4<unit>cups</unit></quantity> of water in a saucepan until it reaches <temperature>71<unit>°C</unit></temperature>

Add <quantity>3<unit>cups</unit></quantity> of katsuobushi

Remove from the heat and let it infuse for 10m

Strain the katsuobushi. The katsuo dashi is ready

Add <quantity>3<unit>cups</unit></quantity> of the dashi to a pan over medium heat

Add <quantity>½<unit>cup</unit></quantity> of soy sauce

Add <quantity>¼<unit>cup</unit></quantity> of sake. Bring to a simmer

Add <quantity>1<unit>tbsp</unit></quantity> of white sugar and stir to dissolve

Remove from the heat and let it cool at room temperature. The tsuyu is ready

Peel <quantity>1</quantity> daikon radish

Grate it through a medium hole

Press the daikon and discard liquid to get<quantity>1<unit>cup</unit></quantity>. Reserve the daikon

Add water to a large pot and bring it to a boil

Add <quantity>400<unit>g</unit></quantity> of udon noodles and cook for about 10m until al dente

Thinly slice <quantity>3</quantity> scallions

Drain the udon. Wash it with cool water

Transfer the udon to a bowl and soak it with <quantity>¾<unit>cup</unit></quantity> of the tsuyu

Add a handful of the grated daikon and make a nest in the middle to add <quantity>1</quantity> egg yolk

Add a handful of the sliced scallions. The bukkake udon is ready

Enjoy!