Ingredients
-Katsuobushi, dry bonito,
-Niboshi, boiled-dried fish,
-Sugar,
-Mirin,
-Soy Sauce.

Soba Tsuyu is made from two different sauces.
One is Kaeshi, and other is Dashi.
Kaeshi could be matured for long time.
Dashi has to be cooked every time you make Soba Sauce.

Let's make Kaeshi.
First, add soy sauce (200cc).
add, Mirin (60cc)
add sugar (60g)
Soy Sauce : Mirin : Sugar = 3 : 1 : 1

Then heat it up to melt sugar.

Don't let it boil. Stop it before it's get boiled.
Not this time, but put this in a bottle and mature for more than a week.

Now let's make Dashi.
Put boiled-dried fish in a water and boil them from water.

When it's boiled, add one grab of dried bonito.
Usually, you never let dried bonito boil for long time,
but this time boil them more than 15 min.
Dashi is ready, use kitchen paper and let filter them.

Let's mix them to make Soba Tsuyu.
Add one scoop of Kaeshi.
Then add three scoops of Dashi.
That's it.