Scrape the skin off of the burdock root, cut to sizes that fit into cooking pot (refer to Helpful Hints), and soak in water for a few minutes.
Boil water in a pot, add a small amount of vinegar, and boil the burdock root.
While boiling the burdock root, combine the marinating sauce ingredients.
Strain excess water from the burdock root, and pound them with a rolling pin. (The photo shows them before pounding.)
Cut into 5 cm lengths, and half the thick pieces lengthwise, or else cut them in half again.
Put the cut pieces of burdock root in the marinating sauce. Stir from time to time to allow the sauce to distribute evenly.
It's ready to serve after a few hours, but even tastier if left to marinate overnight.
Story Behind this Recipe
I saw this recipe in a book or somewhere, but there wasn't enough tartness, so I added a bit more to suit my taste.
If you cut the burdock root into 5 cm lengths before boiling, when it comes time to pound them, you may pound your hand instead. This is why you should cut them up into long pieces that fit into your pot first, then chop them up after pounding them.