Makes a large pot - enough for 12 people, so make it all and freeze half

2 1/2 gallons of water
3/4 lb to 1 lb of beef brisket (if you like it meatier go for the 1 lb of brisket)
1 large onion, peeld
10 cloves of garlic
2 1/2 cups of dried seaweed, or about 90 grams (see photos for more details)
3 tablespoons good sesame oil
2 tablespoons soup soy sauce 국간장 (if you can get it - otherwise you can substitute regular soy sauce or don't use it at all)
Salt to taste

Preparing the seaweed

Measure out your seaweed, and then put in a bowl with lots of water to cover it.  The seaweed with begin to expand, soften and become much more voluminous as it soaks up the water.

After 30 minutes, drain the seaweed and give it a rinse.  There is often some sand or some other sediment so giving it a rinse is a good idea.   Trim into bite sized pieces if necessary then allow it to drain and set aside.

Preparing the stock
Put beef brisket in a large bowl.  Cover completely with cold water.  Set aside for at least 45 minutes, so that you can drain all the blood.  Doing this step helps create a much cleaner broth without the scum that you have to skim off.

In a large stock pot, add 2 1/2 gallons of water.  Bring water to a boil. To the boiling water add onion, garlic cloves and beef brisket.  Bring to a boil again, then reduce heat to medium, cover and allow to simmer for at least one hour. 

At the end of the hour, take a chopstick and poke it into the center of one of the brisket pieces.  The chopstick should go easily in as the beef is tender.  If it is hard to poke the chopstick, cook for an additional 15 minutes, until beef is tender.

Remove beef, onions and garlic from soup stock.  Set soup stock aside, and when the beef is cool, shred into bite sized pieces.
 
Preparing the soup
You will need another large stock pot or you can remove pour the broth into a holding container until needed.  Heat pot over medium heat and then add sesame oil.  Add drained seaweed.  There should be a satisfying sizzle when you add the seaweed.  Saute the seaweed for a minute and then add soy sauce (optional) or a teaspoon of salt.  Continue cooking for another minute and then pour the soup stock over the seaweed.  Add beef pieces and bring to a boil.  Check seasonings and adjust as necessary.  Serve.

(A Note:  Salt does take a bit of time to melt, so make sure you allow for salt to dissolve before you taste and add additional salt.  Also, as each set of seaweed is different, it is difficult for me to say how much salt is needed, which is why you need to adjust your seasonings accordingly.)