Japanese Clam Soup (Asari No Sumashijiru)

Japanese Clam Soup (Asari No Sumashijiru)

The Spruce / Sonia Bozzo

Prep: 30 mins
Cook: 15 mins
Total: 45 mins
Servings: 4 servings
Nutrition Facts (per serving)
168 Calories
2g Fat
6g Carbs
29g Protein
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Nutrition Facts
Servings: 4
Amount per serving
Calories 168
% Daily Value*
Total Fat 2g 3%
Saturated Fat 0g 1%
Cholesterol 76mg 25%
Sodium 1453mg 63%
Total Carbohydrate 6g 2%
Dietary Fiber 0g 1%
Total Sugars 0g
Protein 29g
Vitamin C 27mg 135%
Calcium 115mg 9%
Iron 3mg 18%
Potassium 714mg 15%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

A simple yet classic Japanese clear soup of short-neck clams is not only delicious but is easy to make with very few ingredients. In Japanese, clear soups are known as sumashijiru. This clear soup of clams is called asari (clam) no (of) sumashijiru and pairs wonderfully with any Japanese meal.

Similar to other shellfish, short-neck clams, or asari, have quite a bit of flavor packed within their small shells and require very little seasoning. For this soup, the clams are cooked in a pot of hot water until they open. Those clams that do not open must be discarded as they are not fit to be consumed. The broth becomes a cloudy gray color with delicate flavors of the sea, and that's when we know it’s ready. The soup is seasoned with salt to taste. To bring out the flavors of this delicate broth, very small strips of lemon peel are used to garnish the soup. This adds just enough freshness and acidity to help this soup shine.

If you’re interested, other variations of asari sumashijiru incorporate the use of a bonito (katsuo) based dashi stock, or the use of a dashi konbu (dried kelp) stock, and a hint of soy sauce.

An increasing amount of farmed asari, or littleneck clams, are available at local grocery stores. Typically, farmed clams are scrubbed and sand has been removed prior to their being packaged for sale. Therefore, as soon as you get home they are ready for use. Regardless, if you feel compelled to do so, feel free to soak them in fresh water for up to an hour to remove any excess sand.

If you are using wild clams, scrub them clean and then soak them for up to an hour in a bowl of fresh water to help remove sand. For best results, both farmed and wild clams should be cooked the same day they are purchased.


  • 1 pound manila clams (live, in shell, about 12 to 16)

  • 5 cups water

  • Kosher salt, to taste

  • 1 lemon, zested, for garnish

  • Mitsuba (wild Japanese parsley), for garnish

Steps to Make It

  1. Gather the ingredients.

    Japanese Clam Soup (Asari No Sumashijiru) ingredients

    The Spruce / Sonia Bozzo

  2. In a medium pot, bring water to boil. Reduce heat to medium and add a bit of salt to the water (approximately 1/2 to 1 teaspoon salt).

    salted water in a pot

    The Spruce / Sonia Bozzo

  3. Add fresh clams directly into boiling water. Cook until all of the clams open. If there are any unopened clams, remove them from the pot and discard.

    clams in a pot of water

    The Spruce / Sonia Bozzo

  4. While the clams are cooking, zest lemon rind using a peeler or a microplane.

    zest the lemon into a bowl

    The Spruce / Sonia Bozzo

  5. Serve four to five clams in small soup bowls and pour broth over them. Garnish with lemon zest and the Japanese parsley, if using, and serve immediately.

    Japanese Clam Soup (Asari No Sumashijiru) in a bowl

    The Spruce / Sonia Bozzo