Place the Kombu and 1 litre of water into a jar with a lid or leave it in the pot you will be used later with a lid on top to cover it. Let it sit at room temperature for no less than 30 minutes or overnight on the counter or in the fridge (Best left overnight). It should not be left in a hot place. 

Add the dried shiitake mushrooms to the other 1 litre of water. Let them dehydrate. This may vary on how dried the mushroom is, but somewhere between 3 hours to overnight. They can be left on the counter. 

Place the kombu and the water into a pot, if you have not already done so. Place the pot on a stove heater at medium to medium-low. 

You want to slowly heat up the stock. When it is about to come to a boil, quickly remove the kombu from the pot. If the kombu is overcooked it becomes slimy and will result in a slimy and bitter stock.

Once the kombu has been removed add in the shiitake mushrooms. Let the stock come to a gentle boil and let the mushrooms cook for a few minutes. 

Turn off the heat and strain the stock. 

You now have Shojin Dashi. You can store it in the fridge, freeze it for later or make miso soup.