Kobujime was originally developed to preserve fresh fish for a longer time. In Toyama Prefecture, they even kobujime-nize seasonal vegetables and tofu!
The fish with a relatively large amount of fat tends to overwhelm the kombu’s flavor so let the ingredients sit for a longer time. Red-fleshed fish often discolors when leaving it for a while so you might want to avoid using it.
Some kobujime recipes lightly sprinkle salt on sliced sashimi but we leave the salt out since the slight saltiness of kombu is enough to bring out the flavor.
The leftover kombu can be used to make a dashi stock or enjoyed as an ingredient in oden, a type of hot pot or nimono, a Japanese stew.