Wikipedia lists "grated yam" as an ingredient of okonomiyaki. Is it a particular type of yam? Can it be purchased outside of Japan?

== More Info ==
As Mein suggested, I did some more searching on Wikipedia and the internets.

The "yam" in question is Dioscorea opposita or Japanese mountain yam. In Japanese it is known as yamaimo (kanji: 山芋; hiragana: やまいも).

Unlike other yam varieties, dioscorea opposita doesn't need to be cooked before consumption. (Most yams contain harmful substances in their raw state.) The dioscorea opposita still contains "oxalate crystals" in the skin which can irritate the skin.

The dioscorea opposita yam aka Japanese mountain yam. Image copied from wikipedia

This video shows the yam being grated. I've seen this yam grated before and the grated result was very slimy and gooey.

The grater used for yamaimo is different to western style graters. Oroshigane graters have small spikes on the grating surface.

There may be more than one variety of Japanese mountain yam. I saw a reference (now lost) to a variety with dark skin.


2 Answers 2


It's "a slimy potato" - http://en.m.wikipedia.org/wiki/Dioscorea_opposita. It might be available in Asian grocery stores.

You could probably get by without it. Okonomiyaki translates literally as "cook as you like it". It's a savory pancake-like batter, to which is added whatever you want; often whatever you happen to have lying around the kitchen. Much like an omelette, okonomiyaki is a pretty free form thing.

  • Thanks Katie, I've added your link and some info found there to the question.
    – Shannon
    Apr 17, 2011 at 5:53
  • You can substitute grated lotus root (renkon in Japanese) in your okanomiyaki if you can't find any yamaimo.
    – klinger
    Nov 22, 2017 at 7:52

You should have searched a bit more on Wikipedia :)

Yam is not the sweet potato most people know in the US, but a kind of root. For the preparation of okonomiyaki it doesn't really matter which one.

I don't know where you can buy this, but my advise is to ask in your grocery store, market or specialized (African or Asian food) shop.

  • This is not quite correct: okonomiyaki traditionally uses nagaimo yams, which are very "slimy*, as a binding agent. Substituting a non-slimy yam will not have the same results. May 14, 2017 at 2:06

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