Hiyamugi vs. Somen noodles: What’s the Difference?

When Japanese people think of summer noodles served cold/chilled, the first thing that comes to mind is probably Somen (素麺) or Hiyamugi (冷麦) or Hiyashi Chuka (冷やし中華).

Somen NoodlesSomen Noodles

Among them, the first two, Somen and Hiyamugi, are similar wheat noodles that look the same because of which many people can’t tell how they differ from each other.

Somen vs. Hiyamugi

Somen and Hiyamugi are wheat noodles made from the same ingredients; wheat flour, water, and salt, with which Udon noodles can also be made.

Then, how do they differ?

Machine-Made Dried Noodles

Hiyamugi noodles

Hiyamugi Noodles

According to the Food Labeling Standards of the Consumer Affairs Agency,

when Hiyamugi, Somen, and Udon are manufactured by machine and dried, the difference between them comes only from the thickness, as shown below.

Machin-Made Dried Hiyamugi, Somen, and Udon
Type Thickness
Udon noodles Long diameter: 1.7 mm or more
Hiyamugi noodles Long diameter: 1.3 mm to less than 1.7 mm
Somen noodles Long diameter: less than 1.3 mm

Hand-Made Dried Noodles

Meanwhile, when Hiyamugi, Somen, and Udon are produced by hand labor and dried, the definitions of Hiyamugi and Somen are the same; what has a long diameter of less than 1.7 mm.

And the one for Udon is what has a long diameter of 1.7 mm or more, the same as the machine-made version. 

By the way, Hiyamugi and Somen are different in production methods, and the former is close to Udon.

(Reference Page: Kanmen.com, Sozairyoku.jp )


Hi, I'm Tomo, a Japanese blogger living in Niigata Prefecture, Japan. For the purpose of enriching your life, I would like to introduce things about Japan on this blog, especially unique Japanese products, cooking recipes, cultures, and facts and trivia.

2 Responses

  1. August 24, 2018

    […] noodles are made by machine, the differences in their diameter are very clear (there’s a chart in this page when you scroll down a bit). However, when they’re handmade, there’s almost no difference […]

  2. September 30, 2021

    […] ceramic and has a deep interior. The capacity limit is 34 oz. It is perfect for ramen, soba, somen, hiyamugi and udon noodles. There are 4 bowls in each set, which can be put in the dishwasher for easy […]

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