Make the broth: combine 1200 ml water, 10 dried anchovies, and 10 g dried kelp in a medium pot. Bring to a boil over medium heat, then reduce heat to low and simmer for 10 minutes. Remove the kelp after 10 minutes to avoid bitterness; keep simmering the anchovies for another 5 minutes, then strain the broth and discard the solids.