I think you are talking about roasted pork called "cha-shu"; I have made it a few times and came out a quite good. Although I didn't use coke in it.
Here is my recipe.
<Ingredients>
3~4 lbs pork, loin is a good part to use, but any cut should work fine, avoid ribs since it's too fatty
1/2 cup dark soy sauce
3 large cloves garlic, crushed
one 1 inch ginger, thinly sliced
4 scallions, cut crosswise in third
1/2 cup wine
3 cups chicken stock
1 stick cinnamon(optional)
1 tbs oil
1 tsp black pepper
Season the meat with black pepper.
Heat the oil in a large dutch oven or a cast iron pan.
Add and toss scallions, garlic, and ginger in the oil just until heated through, about 1 minute.
Add pork to color evenly.
Add chicken stock, soy sauce, wine and cinnamon stick and bring to a boil. Turn the meat to cover it with liquid.
Reduce the heat and cover the pan.
Simmer, turning the meat every hour and basting it, until it is fork tender, 3 to 4 hours.
I hope this recipe helps you recreate the one you had in Tokyo.
Enjoy!
