Dissolve the dashi powder in the water in a small bowl and add the soy. Mix together, then set aside.
1 tbsp of vegetable oil in a deep pot and saute the beef on high heat.
Add onion, carrot, and potato, and saute together. Pour in the
dashi/soy stock and bring to a boil. Turn down the heat to low and skim
off any foam. Simmer until potatoes are softened. Add the sugar and
mirin and cover. Simmer for about 5 minutes. Simmer until the liquid is
reduced by half. Serve with steamed rice and enjoy!