Lotus root (renkon) is readily available in Japan year-round, but its main season starts in the fall and continues until March. Although it’s called a root, the edible parts are the swollen rhizomes, or the underwater part of the plant, which grow connected like sausage links. In haiku, the phrase “hasune o horu” (“digging the lotus root”) indicates winter.

The oldest written records of eating lotus root in Japan are from the Nara Period (710-94), but there is archaeological evidence that the plant was cultivated at least 2,000 years ago. However, it wasn’t seriously farmed until the Meiji Era (1868-1912), when high-yielding varieties began to be imported from China. Today, the top domestic producer of lotus root is Ibaraki Prefecture, especially the town of Tsuchiura, which proclaims itself to be the “lotus root capital of Japan.”

Festive food: Lacy lotus root slices also make tasty, crunchy additions to sushi and salad. | MAKIKO ITOH
Festive food: Lacy lotus root slices also make tasty, crunchy additions to sushi and salad. | MAKIKO ITOH

Lotus root has a fairly bland flavor with a crisp, crunchy texture retained even after cooking. However, grated lotus root has a sticky, glutinous quality; in this state it’s formed into dumplings or used as a binder. Nutritionally it’s a great source of dietary fiber as well as starch, potassium, vitamin C, trace minerals and even protein. It’s used extensively in shōjin ryōri (Zen Buddhist vegan cooking) and in powdered form it’s used for kanpō (traditional Chinese medicine for a variety of ailments).

A raw lotus root segment has a light brown skin that needs to be peeled or scrubbed off. The inside is a pale cream-brown color, which quickly darkens due to tannins (actually healthy polyphenols) unless it’s soaked in an acidic bath of water with some vinegar.

The most distinctive characteristic of the lotus root is the lacy holes that run through it. Lotus root slices are usually included as part of osechi (New Year’s feast food), since the holes are thought to symbolize a “good and clear outlook” for the coming year. They can be used to add a decorative touch to sushi and salads or stuffed, as in this recipe. Lotus root is also used in stir-fries and in stewed vegetable dishes.

This recipe is for karashi renkon (mustard lotus root). It’s a regional specialty of Kumamoto Prefecture, said to have been invented for Hosokawa Tadatoshi, the lord of Kumamoto, when it was a feudal territory in the 17th century.

Hosokawa had a weak constitution and was advised by a priest to eat lotus root for his health. The head chef of Hosokawa’s kitchen stuffed lotus root with a mixture of mustard and barley miso, coated it with a golden batter colored with turmeric and egg yolk and deep-fried it. Although it evidently pleased the lord greatly, legend has it the recipe wasn’t made public until much later, since the cut surface of the lotus root was said to resemble the Hosokawa kamon (family emblem). Nowadays, karashi renkon is one of the most popular omiyage gifts to bring back from Kumamoto.

Making your own does take some time, but it’s not hard and tastes great when freshly made. Adjust the amount of mustard you use in the miso paste to your taste — I prefer it to have a distinctive bite.

Recipe: Karashi renkon (Mustard lotus root)

Time: Active prep 20 mins., cooking 10 mins.

Ingredients (makes 12 to 16 slices)

• 2 medium sections of lotus root

(about 300 grams total when trimmed)

For the mustard-miso filling:

• 50 grams fresh breadcrumbs

• 1 tablespoon mirin (rice wine)

• 100 grams white (light brown) miso

• 1 tablespoon wa-garashi (Japanese-style mustard)

For the batter:

• 6 tablespoons hakurikiko (cake flour)

• 1 tablespoon soramameko (fava bean flour), or just add 1 more tablespoon cake flour

• 2 teaspoons turmeric

• 1 egg yolk

• Cold water

• A pinch of salt

• Additional flour for dusting

• Oil for deep-frying


Scrub the lotus root to remove any dirt on the surface with a tawashi scrubber or vegetable brush and peel thinly. Cut off the tapered ends until you end up with two fairly evenly sized pieces. They should weigh around 300 grams total at this point.

Boil the lotus root for five to six minutes. Stand them up on their ends (with the holes facing down) in a colander or a flat sieve, and leave for at least an hour to drain.

Put the breadcrumbs in a bowl and sprinkle with the mirin to moisten them. Add the miso and mustard and mix well.

Twist the hole end of a lotus root piece in the miso mix so that it is pushed into the holes. Keep twisting until the paste comes out the other side. Wipe off any excess miso paste and refrigerate the lotus root overnight.

The next day, wipe off any watery miso paste that has come out of the lotus root and dust the lotus root with flour.

Beat the egg yolk and combine with the cake flour, fava bean flour and mustard in a bowl. Add enough cold water to form a fairly thick batter.

Heat the oil to 180 degrees Celsius. Coat the lotus root completely in the batter and fry in the oil until golden and crispy on the outside. Cool completely and slice. Serve as a side dish or as an appetizer with drinks.

This keeps for three to four days in the refrigerator. Any leftovers can be cut up and used in stir-fries or salads.

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