Zaru Soba (Cold Soba with Dipping Sauce)
This Zaru Soba recipe is the ultimate cold soba with dipping sauce—chewy buckwheat noodles and homemade mentsuyu, ready in 15 minutes.
Dish: Zaru Soba
- Total time
- 15 min
- Active time
- 5 min
- Yield
- 4
- Difficulty
- Medium
Ingredients and Constraints
Ingredients
Ingredient watchpoints2 watchpoints
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Katsuobushi
½–1 cup katsuobushi (dried bonito flakes) ((packed; for a more intense flavor, use the larger amount))
The source row includes a form, size, temperature, preparation, or handling detail.
Details and source
Mirin
½ cup mirin ((plus 1 Tbsp, to taste))
The source row includes a form, size, temperature, preparation, or handling detail.
Details and source
Additional ingredient notes
Ingredients for Zaru Soba (Cold Soba)
dried soba noodles (buckwheat noodles) shredded nori seaweed (kizami nori) green onions/scallions wasabi – optional For the dipping sauce (tsuyu) – or use bottled mentsuyu for a shortcut (see Tips) sake mirin soy sauce kombu (dried kelp) ka
Ingredients US CUSTOMARY METRIC 1X 2X 3X
14 oz dried soba noodles (buckwheat noodles) (3.5 oz, 100 g per serving) 6 Tbsp mentsuyu (concentrated noodle soup base) (see homemade recipe below or use bottled mentsuyu) 1⅛ cups iced water (for the dipping sauce) For the Dipping Sauce (C
Notes
Variations Here are a few ways to make this dish your own.
Change up the condiments. Add grated daikon, toasted sesame seeds, or grated ginger to your dipping cup for extra depth.
Method Overview
Structured method notes that are separate from the step timeline.
How to Make Zaru Soba (Cold Soba with Dipping Sauce)
Make the dipping sauce.
Boil sake and mirin to cook off the alcohol. Add soy sauce, kombu, and katsuobushi.
Show 2 more media items
Nami’s Recipe Tips
Read these tips before you cook—they make all the difference!
Use a big pot of water – Soba releases starch fast. A large pot keeps the water temperature stable and prevents noodles from clumping.
Source video
Source video
Method Timeline
Prep
ActivePrep
5 min
Prep time from the source recipe card.
Cook
ActiveCook
10 min
Cook time from the source recipe card.
Total
PassiveTotal
15 min
Total time from the source recipe card.
Step 1
Gather all the ingredients. I make the homemade dipping sauce ahead and keep it in the fridge until ready to use—it's a big time-saver. Short on time? Use store-bought mentsuyu from a Japanese or Asian grocery store.
Image detailsGather all the ingredients. I make the homemade dipping sauce ahead and keep it in the fridge until ready to use—it's a big time-saver. Short on time? Use store-bought mentsuyu from a Japanese or Asian grocery store.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Visual cue
until ready to use—it's a big time-saver.
Checks2
Visual cueInfoVisualuntil ready to use—it's a big time-saver.
Expected state: until ready to use—it's a big time-saver.
HoldingMain recipeSource holding instruction
Gather all the ingredients. I make the homemade dipping sauce ahead and keep it in the fridge until ready to use—it's a big time-saver. Short on time? Use store-bought mentsuyu from a Japanese or Asian grocery store.
Inputs and tools2
Uses
- ½ cup soy sauce
- 6 Tbsp mentsuyu (concentrated noodle soup base)
Why and source
This step has reviewed source-backed guidance.
Step 2
Add ¼ cup sake and ½ cup mirin to a medium saucepan. Bring to a boil over medium-high heat and cook until the alcohol smell dissipates, about several seconds. Add ½ cup soy sauce. Nami's Tip: I add an extra 1 Tbsp mirin for a slightly sweeter sauce. Feel free to adjust to your taste.
medium-high heat
Image detailsAdd ¼ cup sake and ½ cup mirin to a medium saucepan. Bring to a boil over medium-high heat and cook until the alcohol smell dissipates, about several seconds. Add ½ cup soy sauce.Nami's Tip: I add an extra 1 Tbsp mirin for a slightly sweeter sauce. Feel free to adjust to your taste.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Visual cue
until the alcohol smell dissipates, about several seconds.
Checks1
Visual cueInfoVisualuntil the alcohol smell dissipates, about several seconds.
Expected state: until the alcohol smell dissipates, about several seconds.
Inputs and tools2
Uses
- ¼ cup sake
- ½ cup mirin ((plus 1 Tbsp, to taste))
Why and source
This step has reviewed source-backed guidance.
Step 3
Add 1 piece kombu (dried kelp) and ½–1 cup katsuobushi (dried bonito flakes). Nami's Tip: Use the maximum amount of katsuobushi for a more intense bonito flavor.
Image detailsAdd 1 piece kombu (dried kelp) and ½–1 cup katsuobushi (dried bonito flakes). Nami's Tip: Use the maximum amount of katsuobushi for a more intense bonito flavor.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Inputs and tools2
Uses
- 1 piece kombu (dried kelp) ((1 x 1 inch, 2.5 x 2.5 cm per piece))
- ½–1 cup katsuobushi (dried bonito flakes) ((packed; for a more intense flavor, use the larger amount))
Step 4
Bring it to a boil, then reduce the heat and simmer for 5 minutes. Turn off the heat and let it steep until fully cooled to room temperature. Strain the dipping sauce and set aside. This dipping sauce is concentrated and needs to be diluted. Nami's Tip: Make it ahead and store in an airtight container in the refrigerator for up to a month. Don't discard the spent kombu and katsuobushi—repurpose them to make Furikake (Japanese Rice Seasoning).
Image detailsBring it to a boil, then reduce the heat and simmer for 5 minutes. Turn off the heat and let it steep until fully cooled to room temperature. Strain the dipping sauce and set aside. This dipping sauce is concentrated and needs to be diluted.Nami's Tip: Make it ahead and store in an airtight container in the refrigerator for up to a month. Don't discard the spent kombu and katsuobushi—repurpose them to make Furikake (Japanese Rice Seasoning).Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Visual cue
until fully cooled to room temperature.
Checks3
Visual cueInfoVisualuntil fully cooled to room temperature.
Expected state: until fully cooled to room temperature.
TimingInfoTimingfor 5 minutes
Target: 5 minute
Expected state: Bring it to a boil, then reduce the heat and simmer for 5 minutes.
HoldingMain recipeSource holding instruction
Bring it to a boil, then reduce the heat and simmer for 5 minutes. Turn off the heat and let it steep until fully cooled to room temperature. Strain the dipping sauce and set aside. This dipping sauce is concentrated and needs to be diluted. Nami's Tip: Make it ahead and store in an airtight container in the refrigerator for up to a month. Don't discard the spent kombu and katsuobushi—repurpose them to make Furikake (Japanese Rice Seasoning).
Why and source
This step has reviewed source-backed guidance.
Step 5
Bring a large pot of water to a boil (do not add salt). Add 14 oz dried soba noodles (buckwheat noodles), fanning them out to keep the strands separated. Stir occasionally to prevent sticking. Cook according to the package instructions—do not overcook. Nami's Tip: Before draining, reserve 1–1½ cups of the cooking water (sobayu) to enjoy at the end of the meal.
Image detailsBring a large pot of water to a boil (do not add salt). Add 14 oz dried soba noodles (buckwheat noodles), fanning them out to keep the strands separated. Stir occasionally to prevent sticking. Cook according to the package instructions—do not overcook.Nami's Tip: Before draining, reserve 1–1½ cups of the cooking water (sobayu) to enjoy at the end of the meal.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Inputs and tools2
Uses
- 14 oz dried soba noodles (buckwheat noodles) ((3.5 oz, 100 g per serving))
- 1⅛ cups iced water ((for the dipping sauce))
Step 6
Drain the noodles in a sieve and rinse under cold running water, rubbing gently with your hands to remove excess starch. Nami's Tip: Don't skip this step—without rinsing, the noodles will clump together and turn slimy.
Step 7
Shake the sieve to drain well. Transfer the noodles to a large bowl of iced water. Chill the noodles for 30 seconds. Drain well and set aside.
Image detailsShake the sieve to drain well. Transfer the noodles to a large bowl of iced water. Chill the noodles for 30 seconds. Drain well and set aside.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Checks1
TimingInfoTimingfor 30 seconds
Target: 1 minute
Expected state: Chill the noodles for 30 seconds.
Why and source
This step has reviewed source-backed guidance.
Step 8
Place bamboo sieves or mats over individual plates to catch the draining water. Add one serving of soba noodles to each mat and garnish with shredded nori seaweed.
Image detailsPlace bamboo sieves or mats over individual plates to catch the draining water. Add one serving of soba noodles to each mat and garnish with shredded nori seaweed.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Checks1
ServiceMain recipeSource service instruction
Place bamboo sieves or mats over individual plates to catch the draining water. Add one serving of soba noodles to each mat and garnish with shredded nori seaweed.
Inputs and tools1
Uses
- shredded nori seaweed
Why and source
This step has reviewed source-backed guidance.
Step 9
Combine 6 Tbsp mentsuyu (concentrated noodle soup base) and 1⅛ cups iced water in a measuring cup. Check the taste—add more water if it's too salty, and add more dipping sauce if it's too dilute. Divide into individual cups.
Step 10
Chop 2 green onions/scallions and divide among small plates. Add a dab of wasabi (optional). Serve alongside the noodles and dipping sauce. Nami's Tip: When you’re done eating, pour the hot soba cooking water (sobayu) into the leftover dipping sauce and enjoy as a light broth.
Image detailsChop 2 green onions/scallions and divide among small plates. Add a dab of wasabi (optional). Serve alongside the noodles and dipping sauce. Nami's Tip: When you’re done eating, pour the hot soba cooking water (sobayu) into the leftover dipping sauce and enjoy as a light broth.Just One Cookbook · Zaru Soba (Cold Soba with Dipping Sauce) ざるそばDev reference Checks1
HoldingMain recipeSource holding instruction
Chop 2 green onions/scallions and divide among small plates. Add a dab of wasabi (optional). Serve alongside the noodles and dipping sauce. Nami's Tip: When you’re done eating, pour the hot soba cooking water (sobayu) into the leftover dipping sauce and enjoy as a light broth.
Inputs and tools2
Uses
- 2 green onions/scallions
- wasabi
Why and source
This step has reviewed source-backed guidance.
Step 11
Keep any leftover homemade dipping sauce in a clean, airtight container in the refrigerator for up to a month. Cook the soba noodles just before serving—they clump and lose their texture as they sit.
Handling and Storage
Reviewed hold, storage, make-ahead, and service-timing guidance.
Variations
Here are a few ways to make this dish your own.
Change up the condiments. Add grated daikon, toasted sesame seeds, or grated ginger to your dipping cup for extra depth.
What to Serve with Zaru Soba (Cold Soba)
Turn Zaru Soba into a full summer spread with these Japanese dishes.
Vegetable Tempura or Shrimp Tempura – Add crispy tempura to make tenzaru (天ざる), the classic summer pairing served at soba restaurants across Japan. Tofu Salad with Sesame Ponzu Dressing – Leafy greens, corn, and wakame seaweed in a bright, tangy dressing add a refreshing contrast.
Storage Tips
To store: Keep leftover homemade mentsuyu in an airtight container in the refrigerator for up to a month.
Cook the soba noodles just before serving. They clump together and lose their texture as they sit.
Can I use store-bought mentsuyu for the soba dipping sauce?
Bottled mentsuyu from a Japanese or Asian grocery store works.
Dilute it according to the package directions—the ratio may differ slightly between brands and the homemade version. That said, making the sauce from scratch takes only 15 minutes, and the flavor is noticeably richer.
What is sobayu and how do I use it?
Sobayu (蕎麦湯) is the starchy water left in the pot after boiling soba noodles.
Buckwheat is a good source of fiber, protein, and nutrients, and some of that goodness carries over into the cooking water. At the end of the meal, pour hot sobayu into your leftover dipping sauce and drink it as a light broth—a tradition at soba restaurants across Japan.
Learn More
Extra cooking notes, tests, and source details kept out of the step-by-step method.
Testing notes
Useful tests and side-by-side notes after the method is clear.
What is Zaru Soba (Cold Soba)?
Zaru soba (ざる蕎麦) is Japan’s signature cold soba dish made with buckwheat noodles, first enjoyed during the Edo period (1603–1868).
The name comes from the zaru, a bamboo strainer that holds the noodles lifted so excess water drains away. Diners dip the chilled noodles into a cup of savory tsuyu sauce—made of soy sauce, mirin, sake, and dashi—and brighten each bite with green onion and wasabi.
What is the difference between soba and zaru soba?
Soba refers to buckwheat noodles and all the dishes made with them—including soba noodles in hot soups and soba noodle salads.
Zaru soba is one specific preparation: cold soba noodles served traditionally on a bamboo mat with dipping sauce. Follow my recipe in this post, and you’ll have it on the table in 15 minutes.
Recipe structure
Components and intermediate outputs created by the method.
Main recipe
Recipe card ingredients and steps.
4
Garnish
Source step 8 creates or uses garnish.
Sauce
Source step 1 creates or uses sauce.
Extra useful notes
Short source-backed recommendations and facts that do not need a step.
Here are a few ways to make this dish your own.
Here are a few ways to make this dish your own.
Change up the condiments. Add grated daikon, toasted sesame seeds, or grated ginger to your dipping cup for extra depth.
Change up the condiments. Add grated daikon, toasted sesame seeds, or grated ginger to your dipping cup for extra depth.
Try a different soba blend. Ju-wari soba (十割そば) is 100% buckwheat—earthy and crumbly with a strong aroma.
Try a different soba blend. Ju-wari soba (十割そば) is 100% buckwheat—earthy and crumbly with a strong aroma. Hachi-wari soba (八割そば) blends 80% buckwheat with 20% wheat for a smoother, springier texture.
Go gluten-free. Use 100% buckwheat (ju-wari) soba and tamari in place of regular soy sauce.
Go gluten-free. Use 100% buckwheat (ju-wari) soba and tamari in place of regular soy sauce.
Try a different flavor soba. Cha soba (茶そば) has a pale green, mildly earthy flavor from matcha powder.
Try a different flavor soba. Cha soba (茶そば) has a pale green, mildly earthy flavor from matcha powder. Ume soba (梅そば) has a soft pink tint and a subtle, fruity flavor from Japanese ume plum.
Make Oroshi Soba. Serve the chilled noodles in a bowl with dashi-based sauce and top with grated daikon, dried bonito flakes, and tempura scraps.
Make Oroshi Soba. Serve the chilled noodles in a bowl with dashi-based sauce and top with grated daikon, dried bonito flakes, and tempura scraps.
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Zaru Soba (Cold Soba with Dipping Sauce) ざるそば
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