Umami Mart Registry

On paper, nagaimo sounds like a miracle food. Nagaimo is a type of yam with hardly any calories, while simultaneously lowering blood pressure and cholesterol. It's also full of potassium and fiber and ideal for the diet of a diabetic. And that list doesn't even include its most popular benefit.

It's been said that during the Edo period, men added nagaimo to their bath water to increase their sexual virility. It was Edo's version of Viagra. Their logic lied in the fact that the slimy element in the yams enabled the efficient break down and subsequent absorption of protein. This allowed men to get the "most" energy out of the proteins they ate.


Sounds like a bunch of crazy "eastern" hoo-haw to me... I eat yamaimo because of its unique texture and ability to add another dimension to certain foods.

Adding grated nagaimo and raw egg is one way to pump up a bowl of rice. You may remember this picture from one of my posts three years ago. Tororo is the sticky slimy substance that results from grating nagaimo. Honestly, the nagaimo doesn't taste like much. It is slightly nutty bringing out the flavor of each rice grain. The real attraction is in its slimy texture.

Mangetsu Mugi-toro Don
Mugi Tororo Don at Mangetsu in Hatagaya, Tokyo

Mangetsu Mugi-toro Don
The nagaimo once mixed with the egg

Here's a shot of a guy grating the nagaimo, for a fresh soba feast in Nagano last year.


Soba, you ask? Yes! Nagaimo is a classic accompaniment to zarusoba (cold soba). The slimy slurp effect is so satisfying.


Another example of pumping up a food with nagaimo is adding tororo to okonomiyaki (Japanese savory pancake). Nagaimo seems to add more heft to the okonomiyaki batter, giving it a little bit more saveur. This photo is from the recent Umamimart archives.

Photo Johnny Lopes

According to Vanesa, nagaimo also encourages silly times.

Photo Johnny Lopes

In the world of yams, nagaimo is the exception to the rule. Not because it's the natural Viagra of the east, but because it is the only known yam that can be eaten raw.

One of my favorite ways is to eat nagaimo raw is to julienne it and drizzle it with some soy sauce and add a dollop of wasabi on top. The texture is somewhat like an Asian pear with lots of slimy coating.


With some soy sauce and wasabi, I am transported to a valley village in Japan with the sound of a running creek whispering in my ear. In the distance, I can see a woman working in a rice paddy and hear the meditative whistle of the tofu man rattling his cart on the cobble-stoned road approaching.

That whistle turns into the ear piercing whistle my OXO tea kettle screaming in my Berkeley apartment. BACK to reality.

With raw foods and foam being all the rage for a while in fancy cooking, I am surprised nagaimo hasn't caught on. But then again, maybe the "east" wants to keep it that way so they can have a steady supply of yamaimo-spiked bathwater.

Line up men, get your nagaimo.
Column: Japanify


  • One of my favorite foods! But always so pricy. I find it for cheaper at Chinese and Korean markets, rather than Japanese grocers.

    Kayoko on

  • weirdly i don’t like this grated but i love it sliced.

    wen on

  • Shame on you.

    I wonder how Koreans and Chinese eat nagaimo.

    Not to be mistaken for naGAYmo.

    Kayoko on

  • Of course. How could I NOT mention the Korean market!

    yoko on

  • Soup! Is it grated and then cooked? What do they combine it with?

    yoko on

  • FYI chinese people make soup with this and in its dried form its used in chinese medicine.

    wen on

  • ながいもをすりおろし、きぬごしtofuにいれます。

    kenji miura on

  • So drying it, then making it into a powder makes this the Chinese Viagra!

    Kayoko on

  • yoko, nagaimo that’s available here are way too watery, but you can try to mix it with a bit of corn starch, and egg white,to steady it up, then spoon it out in soup. It makes very soft dumpling. And a lot of Japanese wagashi has nagaimo as ingredients.

    yamahomo on

  • i haven’t made it myself, just had it at relatives houses… it’s kind of a medicinal soup had around cold season to build up our strength lol. it is sliced and cooked in the soup, usually with porkbone or something.

    wen on

  • ながいもをヨーグルトみたいに食べるのは考えたころない食べ方ですね!ながいもを甘いものと食べるのはおもしろい。ながいもは和菓子の材料にもなりますでしょうか。。。

    yoko on

  • Yama! Your next creation with nagaimo please!

    Kayoko on

  • Ooh, that’s interesting about making it more firm with corn starch and egg whites to make a dumpling. Do you add any flavoring to it?

    yoko on

  • Hi, found your website from searching some articles on nagaimo. Thanks! Gave me some good ideas.
    My Japanese host mum taught me a new way of processing nagaimo over the New Year’s break: peel and then slice thinly and then dry-fry it using a non-stick pan. It takes away the slime a little bit, but preserve enough slime in, and then you can eat it like chips! I like to use it as starch source in green-salad.

    Tari on

  • 和菓子のざいりょうは、イモがおおいです。いもとさとうはあいます。

    kenji miura on

  • Tari, that sounds like a great way to prepare nagaimo. The texture must be satisfying.

    yoko on

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