Somen: summer's coldest noodle

There's a particular kind of Japanese summer afternoon, heavy and humid, the cicadas going like a power tool, when the very idea of a hot meal feels like a personal insult. That's somen weather.

Somen (素麺, often written そうめん) are Japan's thinnest wheat noodles, and in summer they're served the way little else is: ice-cold, glistening, piled in a glass bowl with ice cubes clinking against the sides. They take minutes to make and seconds to eat. I'd argue no other noodle is so perfectly designed for the weather it's eaten in.

The thinnest noodle in the cupboard

Somen is made from wheat flour, water and salt. In the traditional hand-stretched kind, tenobe (手延べ), the dough is coated with a little oil and pulled, again and again, into longer and finer strands, then hung on poles to dry in long, pale curtains. Machine-made somen is cut rather than stretched, and by Japan's labelling standards it must be under 1.3 millimetres thick.

Most somen is sold dried, in neat bundles tied with paper bands. Because the strands are so fine, they cook in a minute or two. Boxed sets of good somen are also a classic summer gift, the kind of present that's practical and quietly generous at the same time.

How to serve it properly cold

The method is simple, but each step matters.

1. Boil briefly. Use plenty of water and follow the packet, which often means just a minute or two.
2. Rinse hard. Drain the noodles and wash them under cold running water, rubbing them gently between your hands to remove the surface starch and oil. This is what stops them turning gummy.
3. Chill. Plunge them into iced water until they're properly cold, then drain well.
4. Serve on ice. A glass bowl, a few ice cubes and small bundles of noodles look as cool as they taste.

Alongside comes a cup of mentsuyu (めんつゆ), a dipping sauce of dashi, soy sauce and mirin, and a little plate of condiments: sliced green onion, grated ginger, toasted sesame, shredded shiso (しそ) leaves and myōga (茗荷), a pinkish, gently sharp bud from a plant in the ginger family. Lift a small bundle, dip, slurp, repeat.

Some packets include a few pink or green strands among the white. They taste the same, but they make a plain bowl look like a party, and I think that counts for something.

Nagashi somen: noodles on the run

Then there's the version that turns lunch into a game. Nagashi somen (流しそうめん), "flowing somen", starts with a long length of bamboo split in half to make a flume. Cold water runs down it, someone at the top drops in a handful of noodles, and everyone lined up along the channel tries to snatch them with chopsticks as they rush past. Whatever escapes is caught at the bottom.

It's a summer favourite at community events and festivals, and some restaurants and tourist spots offer it too. You can even buy small tabletop machines for home that send noodles swirling around in a current of water. As a way of eating efficiently, it's hopeless. As a way of spending a hot afternoon with other people, I can't think of much better.

Where it comes from

Somen's ancestors are generally thought to have arrived from China, and several Japanese regions have long histories of making it.

Miwa (三輪), in Nara Prefecture, near the ancient Ōmiwa Shrine, is often cited as one of the oldest somen-making regions in the country, and Miwa somen is still a respected name.

Ibo no Ito (揖保乃糸) is a famous brand of hand-stretched somen from the Banshū area of western Hyōgo Prefecture. It's one of the best-known names in somen, and a familiar sight on Japanese shop shelves.

Shōdoshima (小豆島), an island in the Seto Inland Sea that belongs to Kagawa, the prefecture better known for Sanuki udon, is also known for its hand-stretched somen.

Somen's cousins

Once you know somen, a few close relatives come into focus.

• Hiyamugi (冷麦) is slightly thicker than somen, sitting between it and udon, and is usually served the same way, ice-cold with dipping sauce. Side by side the difference is subtle; on the tongue, hiyamugi has a touch more chew.
• Nyūmen (にゅうめん) is somen served hot in a light broth, for when summer is over or you simply want something soothing.
• Sōmin chanpurū (ソーミンチャンプルー) is Okinawa's take: somen stir-fried with vegetables, often with canned tuna or meat.

If you like the cold-noodle ritual, soba has its own version, with a dipping sauce, condiments and a warm finish; our soba guide explains it. And for more on how Japan eats through the year, see our piece on the seasons of soup.

Somen is proof that a dish doesn't need to be complicated to become a ritual. Boil, rinse, chill, dip. It's less a recipe than a way of agreeing with the weather.