Wash the ginger and grate into a plastic bag, peel and all. Add the shio-koji and rub over the bag to mix.
Make some cuts along the grain in the pork. Cut off the fat if you like. Make sure you cut notches into any sinews.
Put the pork into the plastic bag and rub the ingredients over the bag. Take out the air from the bag, close it up and leave to marinate in the refrigerator for at least an hour.
When it's time to cook, heat a pan (without oil) and sauté the pork on both sides until browned and cooked through.
Drizzle the mirin and simmer over low heat until there's no liquid left in the pan. Turn off the heat before it burns, and it's done.
Slice the meat into easy to eat pieces. This reduces the number of utensils you have to wash up too. It's also good with mayonnaise.
Story Behind this Recipe
I wanted to make a pork dish using shio-koji, and my mother had given me some meat to use as ginger pork or tonkatsu, so I tried making this version of ginger pork.
It's best to brown the meat well. This way the surface will caramelize as if you used soy sauce when you add the mirin. I used hon-mirin this time (not mirin seasoning). If the meat you have is thin, you can reduce the marinating time.