Scrub potatoes clean but don't peel. Put in a heavy bottomed pot and fill with water 2/3 way up the potatoes.

Cover pot with lid and turn on medium heat. When the water starts to boil, turn heat down a bit and let cook for 15 minutes.

After 15 minutes, drain out the water, keeping the potatoes in the pot. Put back on the heat and brown the skins a little.

Add butter and soy sauce to the pot. Toss the potatoes so they get coated in the melted butter and browned in the soy sauce.