Debone the chicken legs, trimming off excess skin and fat. If using chicken chops, cut off the joint.
Tie up the chicken legs using kitchen twine.
Heat up a large non-stick skillet over medium high heat. When hot, add the chicken and sear, until browned on all sides, about 4 to 5 minutes per side.
In a large pot over medium high heat, add the water, konbu, shiitake mushrooms and chicken.
Bring the mixture to a boil. When the water starts to steam, remove the konbu from the pot.
Add the sugar, salt, the soy sauces, sweet sauce and rice vinegar mixture. Stir until the sugar is dissolved.
Reduce the heat to medium and simmer, uncovered, 25 minutes.
Remove the pot from heat, transfer the contents to a large bowl and let cool to room temperature.
Cover the surface of the chicken and braising liquid with a thick paper towel, to ensure the flavors are evenly absorbed by each piece of chicken.
When the chicken has cooled to room temperature, remove from the seasoning liquid, and snip off the kitchen twine.
Reserve the liquid in an airtight container, for use when making ramen eggs.
Slice into 1/4-inch slices and use as desired. If not using immediately, store unsliced in an airtight container in the fridge for up to a week, or up to a month in the freezer.