Using a bamboo skewer, take the vein out from in between the shell parts. Leave the shell on.
If you pull the vein (digestive tract) out slowly, it will come sliding out.
The pointy parts of the shrimp are dangerous so cut them off with kitchen scissors. Rinse quickly and dry.
Put the flavoring ingredients in a pan and bring to a boil.
Add the shrimp, and cook them through. It depends on how big they are, but this takes 3 to 5 minutes.
When the shrimp are cooked, take them out and line them in a shallow tray. If the shrimp don't all fit at once, repeat in batches until all the shrimp are cooked.
Leave the simmering liquid as is to cool down.
Put the cooled down shrimp and simmering liquid in a ziplock bag, eliminate as much air as possible and store in the refrigerator. Leave to marinate at least overnight to let the shrimp absorb the flavors.
If you seal it well and keep it in the refrigerator, you can make it on the 30th of December and it will be perfect to eat on the 3rd of January!
I changed the top photo. This is the former photo.
You can use light colored (usukuchi) soy sauce if you prefer.
When cooking the shrimp, neaten them up with chopsticks, so that when they are done they will line up together nicely. There's no need to secure them with toothpicks.
I received feedback from someone that it got too salty. Since there isn't much simmering liquid, if you have a wide pot the liquid may become too reduced and concentrate (continued...).
(..continuation) Don't turn the heat up too high, and only cook the shrimp for a total of about 10 minutes. Use 10 shrimp as the unit, and increase all the ingredients incrementally if you want a bigger amounts.
Story Behind this Recipe
I wanted to make delicious shrimp that stayed moist for osechi (New Year's feast food), so I looked through old magazines and so on and studied it a lot before making this.
You can use headless shrimp too, but head-on shrimp are better since they have the 'miso' inside the heads!