This is a very classic Japanese staple dish. More often than not, I have some variation of it in my refrigerator. The base is hijiki seaweed, which is soaked and reconstituted then cooked in dashi with various other ingredients that give it flavor. It's great to add to a bento box.

This version has carrots and fried tofu in it. Cutting them into fancy shapes is totally optional, but it does make your bentos a bit more fun.

I've used me-hijiki for this but you can use the regular long branch hijiki too.

Kombu, the leathery seaweed that is used to make dashi stock, is packed full of umami. A traditional way to prepare it is as shiokombu (salty kombu) or kombu no tsukudani. Tsukudani is a method of cooking something with soy sauce, sake and/or mirin, and sugar until it's very dark, quite salty and sweet too. It's a preserving method, since the salt and sugar greatly increase the keeping qualities of the food.

Kombu no tsukudani can be tucked into the corner of a bento box to add a little variety. It's also a good onigiri filling. Properly made and stored in the refrigerator, it keeps almost forever.