What Makes Japanese Sweet Potatoes Special?

by Emi Noguchi

We love the Japanese sweet potato so much, we couldn’t help but write them a poem for a primer. We’ve heard brevity is the soul of wit. It seemed only right to keep the basics short and, well, sweet. 

What Makes Japanese Sweet Potatoes Special?

Shall we compare them to the orange type? 

They art more sweet and far more purple-peeled. 

When fall winds blow, this “rescue crop” is ripe.

So should the rice yield fail, there’s yet a meal.

The satsuma-imo needs no aid:

When baked, their natural sugars caramelize.

The flesh transforms: from white to gold remade.

It’s paired with chestnut, feast for tongue and eyes!

Potatoes are native South American crops. 

By Spain’s colonial ships they came east. 

The Philippines and China, Ryukyu Kingdom? All stops.

Now the satsuma-imo is called...“Japanese.”

Well, so long as men can eat, or eyes can see, 

So long lives this poem, which makes us hungry. 

An Introduction to Japanese Sweet Potatoes

Now that we’ve got that out of our systems, let’s dig a little deeper: it’s harvest time, and satsumai-imo, the famed Japanese purple sweet potato, is ready for picking. As you’ve (hopefully) gathered, the Japanese sweet potato is used primarily in sweets. Most fans of Japanese snacks or media are familiar with the attention Japanese folks pay to regional and seasonally-specific foods. Each prefecture has at least one nationally famous agricultural product. The ancient Japanese calendar, modelled after China’s Twenty-four Solar Terms, celebrates seventy-two microseasons. Even in convenience store chains, you’ll find that Japanese snacks will cycle not just with holidays, but with what’s in season. In addition to the Japanese purple sweet potato, kabocha and chestnuts are the taste of autumn. 

Perhaps it goes without saying, then, that in the fall, one will find plenty of Japanese snacks flavored with sweet potato. We’ve actually got a collection of Japanese sweet potato snacks. This rich, golden sweet potato cake is made from Naruto Kintoki, a Japanese sweet potato grown in the area around Naruto City in Tokushima Prefecture. Incidentally, Tokushima-ken is one of the top five producers of Japanese sweet potatoes, which together grow over 80% of the nation’s total. This golden cake is a great example of a Japanese sweet potato recipe following a long tradition of dishes designed to “let the sweet potato do the talking.” Japanese sweet potatoes—even the Japanese purple sweet potato—really are that vibrant gold inside! This cake is also flavored with rum and cinnamon, which reminds us: if anyone has a Japanese sweet potato recipe for pies, please step forward and share that with us now!

We’d like to mention two more Japanese sweet potato products available on Bokksu Marketplace. First is an elegant “langue de chat” cookie gift box. Originally a French confectionery, the japanese langue de chat is generally a rectangular butter cookie with chocolate filling. There are four flavors in this set, but the highlight for our purposes is the “Sweet Potato.” The next and final product that we had to mention is the truly delightful Buson Haiku Senbei Mix, which features a variety of flavors ranging from matcha to sakura-and-peanuts to, you guessed it! Japanese sweet potato! Aside from its fun and very-much discernable assortment of flavors, this senbei mix is a crowd-pleaser for its adorable shapes, which include flowers and leaves. For those who like a call-back, these rice crackers were also inspired by the haiku of master-poet Yosa Buson!

What Makes Japanese Sweet Potatoes Special

A Sweet Japanese Sweet Potato Recipe

If you’re interested in making your own Japanese sweet potato recipe, this one (called yaki-imo) couldn’t be easier: bake it in the oven, then mash with a fork! If nutmeg, cinnamon, or even maple syrup (which, yes, is generally harvested in the winter) call out to you, dress that sweet potato up and enjoy. If you eat it plain, that will be perfectly delicious, too. You’ll find Japanese sweet potato in karaimo kankoro mochi. The latter requires boiling and sun-drying sliced sweet potato before combining glutinous rice and assembling (aka mashing). This would stretch the volume of valuable rice and provide important nutrients through the winter! (Fun fact: “karaimo” is still sometimes used to mean Japanese sweet potato, though it once literally meant “potato from China.”) There are so many other Japanese sweet potato recipes, but the one we’ll end on is the use of sweet potato starch to make “spring rain,” a particularly poetic name for vermicelli. 

The Japanese Sweet Potato's Nutritional Value

Japanese sweet potato nutritional value? High! High in fiber, potassium, and B-6. A cup of cubed Japanese sweet potato even contains calcium and an average 2 grams of protein. Like its orange counterpart, it also contains plenty of Vitamin C and iron. Delicious, nutritious, Japanese sweet potatoes are also...fun! In the autumn, tourists can dig up sweet potatoes like one goes apple-picking. Sweet potatoes are also used in early education to make stamps for printing. 

Believe it or not, there’s actually a lot more to say about the Japanese sweet potato, but we’ll have to leave it at that because, well, we’ve dug deep enough for now. Take care this fall, and if you get the chance, do yourself a favor and try out a baked, mashed satsuma-imo. You will be glad you did!

Author Bio

Emi Noguchi is a fiction writer, blogger, and freelance writing instructor, and co-founder of MFA App Review. After studying standard Japanese at Columbia University, she picked up Kansai-ben while living in Osaka and some Awa-ben in her paternal hometown in Tokushima. Emi is a 2020 recipient of the John Weston Award and holds an MFA in Creative Writing from the University of Arizona. You can read her work in Essay Daily, The Spectacle, and Fairy Tale Review. Emi is currently writing a novel about diasporic illnesses, art-making, and traditional Japanese puppetry.