Hiyashi Yamakake Udon (Chilled Udon with Grated Japanese Mountain Yam)

Hiyashi Yamakake Udon (Chilled Udon with Grated Mountain Yam)
Chilled Udon with Grated Mountain Yam (Hiyashi Yamakake Udon)

Judy Ung

Prep: 10 mins
Cook: 3 mins
Total: 13 mins
Serving: 1 serving

Hiyashi yamakake udon or chilled udon noodles with raw grated Japanese mountain yam (also known as nagaimo or yamaimo) is a traditional Japanese noodle dish that is often enjoyed during warmer weather or hotter summer months.

It is a fairly simple dish in that udon noodles are cooked, chilled, and then served with a generous portion of freshly grated Japanese mountain yam (nagaimo or yamaimo). This dish is great for a light lunch or dinner.


  • 1 package frozen sanuki udon noodles
  • 1 cup of ice cubes
  • 1 cup Japanese mountain yam (nagaimo or yamaimo, raw and grated)
  • 1 cup prepared udon noodles sauce (tsuyu)
  • 1 tablespoon green onions (thinly sliced)
  • 1 tablespoon Kizami nori (thinly sliced dried seaweed)
  • Optional: 1/2 tablespoon grated daikon radish
  • Optional: 1/2 teaspoon Wasabi (Japanese horseradish)

Steps to Make It

  1. Gather the ingredients.

  2. Boil water, add 1 block of the frozen udon noodles and cook for 3 minutes. (Because these are pre-cooked, boil them only until they’re heated through and serve al dente.)

  3. Drain the udon noodles in a colander, rinse with cold water.

  4. Add ice cubes to the colander with the udon noodles to chill the noodles. They're very refreshing when served ice-cold, especially in warmer weather. Set the noodles aside, allowing the water from the ice cubes to drain.

  5. Remove the rough outer skin of the yamaimo. (Use a vegetable peeler, but only peel off as much as you will be using. It keeps better in the fridge if it's unpeeled. Also, it's easier to grate if you have some of the rough peel to grip at the top.)

  6. Use a good old-fashioned grater for grating the yamaimo. 

  7. Transfer the noodles to a deep dish or bowl.

  8. Pour grated yamaimo over the chilled udon noodles.

  9. Finely slice green onions. Garnish yamakake udon with green onions, kizami nori (thinly sliced dried seaweed), grated Japanese daikon radish (optional), and wasabi (optional).

  10. Serve udon noodle sauce (tsuyu) on the side. Just before serving, pour the sauce over the yamakake and udon noodles and enjoy.


  • Use frozen sanuki udon noodles for best results. Frozen noodles cook very quickly, and their texture is al dente.
  • Use ice cubes to chill the noodles quickly.
  • Use a traditional grater to grate the yamaimo. It tends to work better than a food processor as this tends to leave small chunks.
  • For a quick and easy lunch or dinner, use prepared udon noodles sauce pre-made and available for purchase at Japanese grocery stores. You can also make a homemade noodle dipping sauce.