Peel the daikon and cut it into 2-3 cm (1 in) rounds. Peel the potatoes and boiled eggs. Cut large fish cakes into bite-sized pieces. Rinse and drain the shirataki. No pre-boiling needed.
Put the water, dashi packet, sake, mirin, soy sauce, and salt in the inner pot of an electric pressure cooker.
Add all the ingredients at once. Do not fill above the max line.
Close the lid, set to sealing, and cook at high pressure for 30 minutes. Let the pressure release naturally.
Open the lid, skim off any foam, and check that the daikon is tender. Taste the broth and adjust with soy sauce or salt. Serve in shallow bowls with some broth.