Add the high-protein wheat flour into a bowl first.

Soba Dough and Noodle Making
Authentic soba dough and noodle-making recipe learned from Chef Nam Chang-soo of Minami, who has appeared on shows like 'Master of Living' and 'Wednesday Food Talk'.
What You'll Need
Instructions
Add Bongpyeong buckwheat flour, which is a strong flour, to supplement the color and protein content.
Measure the total weight of the wheat flour and buckwheat flour to be 1kg.
Sift the flour once to remove any potential impurities, small stones, or husks.
Stir the sifted flour evenly with your hands about two times.
Prepare water equivalent to about 50% of the flour weight, adjusting the amount based on weather and humidity.
Gather the wheat and buckwheat flours together and form a dough.
Knead the dough by hand until it becomes firm.
To form gluten, gather the dough to one side with the bottom facing down.
Use a rolling pin to flatten the dough.
Switch tools slightly to roll the dough out larger into a rectangular shape.
Use the rolling pin to roll it out wide while maintaining a consistent thickness.
Using a noodle cutter, create pleats in the properly spread dough and gather it to one side.
With the pleated dough facing down, use the rolling pin again to flatten it.
Use the noodle cutter to cut the noodles into uniform sizes.
Shake out the cut noodles to finish.