Behead and gut the sardines. Rinse the insides well.
Combine the flavoring ingredients in a pot together with the umeboshi torn in about three pieces, and bring to a boil.
Add the sardines to the pot.
Once it comes to a boil, reduce to low heat, cover with a drop-lid, and simmer for about 40 minutes.
Simmer until the juices are reduced to a small amount.
If you line the pot with parchment paper, add the flavoring ingredients, then the sardines, and then use another sheet of parchment paper as a drop-lid, you can transfer it to your serving plate without the fish falling apart!
Story Behind this Recipe
I bought some fresh sardines. Of the ten I bought, I used 6 for sashimi, and the rest in this recipe.
To tell whether sardines are fresh, look for a taut body, well-defined, glossy scales, and black eyes. They're prone to breaking or falling apart when transferring to a serving plate, so try the process listed in Step 6. It's pretty easy. Give it a try!!