Add 2 cups of water to the seaweed in a pan and bring to the boil
Simmer with lid on for 30 mins (liquid should more than half...if liquid reduces too much add a little more as necessary)
Strain the seaweed retaining the liquid
Rinse pan and add the soy sauce along with peppercorns, shiitakes and garlic - bring to the boil
Add seaweed liquid and simmer for 30 mins
Add wakame powder and simmer for 10 more minutes
Should have reduced by at least half again
Store in airtight container in fridge