Tachikawa Udo Guide: History of Tokyo’s Underground White Vegetable

What is Tachikawa famous for? Tokyo udo, a white vegetable grown 3 m underground: its history, how to eat it, and where its roots spend the summer.

日本語で読む（Japanese version）

Tachikawa’s speciality grows three metres below ground, in the dark. It never sees a single ray of sunlight. It comes up white, and perfectly straight.

Ask people what Tachikawa (立川) is famous for, and I doubt many will answer straight away. Even people who live here would have to think about it. I certainly did. Tachikawa sits in the Tama area — the western half of Tokyo, the part beyond the 23 central wards that most visitors never reach — and what comes to mind first is the crowd outside the station, or the monorail gliding across the sky. A city without a famous product, I had almost decided.

The answer turned out to be under the ground. The City of Tachikawa proudly states that it is number one in Tokyo for the production of Tokyo udo. And that udo is not finished in a field, but in a hole dug three metres into the earth.

Then, almost as soon as I started digging (so to speak), I ran into an odd sentence. The roots that sprout in Tachikawa’s underground pits, it seemed, were mostly not grown in Tachikawa’s fields at all. So where do the roots of Tokyo’s number-one vegetable spend the summer, and what are they doing there? And why go so far away? I decided to follow this white vegetable back through its history to find out.

What is Tachikawa famous for? The answer is three metres underground

What is Tachikawa’s speciality? The surest answer is Tokyo udo (東京うど). The city’s own list of local specialities has exactly two items on it, Tokyo udo and broccoli, and both carry the same headline: “Number one in Tokyo for production.” In the 2022 harvest, Tachikawa grew 52 tonnes of udo, 32.9 per cent of everything harvested in Tokyo. The season runs from mid-December to April. Because it is grown in an underground pit that no light can reach, it is white. And if you want a souvenir, an udo pie and an udo salad dressing are among the officially recommended souvenirs of Tachikawa. There was never any need to go quiet when someone asked what the city was known for.

But first, the vegetable itself, which most visitors to Japan have never heard of.

According to the “food calendar” published by the Tokyo Metropolitan Tama-Fuchu Public Health Center, udo (Aralia cordata, sometimes called Japanese spikenard) belongs to the Araliaceae family, which makes it a relative of Korean ginseng and of taranome, the spring shoots of the angelica tree. Like yam, garlic chives and bracken, it is a vegetable native to Japan. There is the green “mountain udo” (yama-udo) that grows wild in the hills, and the “white udo” (shiro-udo), whose defining feature is its colour. Tokyo udo is a kind of white udo, and one of the Edo-Tokyo yasai — the heirloom “Edo-Tokyo vegetables,” a group that also includes the famous Nerima daikon radish.

There is a reason for the whiteness, and the city explains it in one short line: the white colour comes from growing it in a pit three metres underground called a muro, where no light can enter. Ordinary udo grows wild in the hills and mountains, and it is green. Tokyo udo, in other words, is udo that has never had a suntan.

Tokyo’s metropolitan guide to regional products goes into a little more detail about the inside of an udo-muro, an udo pit. At a depth of about three metres, the pit stays at around 18 to 20°C all year round, and in winter it is sometimes warmed further with heating wires. That is far more comfortable than the ground above in midwinter. It may well be more comfortable than my own room in winter, a thought that left me feeling slightly pathetic.

It is only comfortable for the udo, though. The same guide notes that, to avoid running out of oxygen inside the pit, growers check whether there is enough air by watching the flame of a candle as they work. Going down to tend an underground field takes the precautions of a coal mine. I had been reading about vegetable farming, and suddenly I was reading about mining.

Why was Tachikawa so suited to holes in the ground? The city says that pit cultivation, which had been practised in the Musashino area, matched Tachikawa’s geology — the Kanto loam, which does not crumble easily, and its ability to hold temperature and humidity — and that this is why it became most popular in Tachikawa. Kanto loam is a red earth formed from volcanic ash that fell and piled up over ages. In Sunagawa, in the north of Tachikawa, the city’s cultural-heritage notes record that this soil was useless for rice paddies, and farmers struggled to grow rice. Yet when it comes to digging a hole, the same soil becomes an ally. It does not collapse, and it does not let the warmth escape. Depending on what you want to grow, the reputation of a piece of earth can flip completely.

So where do the roots come from — the root clumps that are carried into these cosy holes every winter? To find out, we have to take the long way round.

From the Heian court to the Edo townsman’s “first of the season”

The city writes that udo cultivation is thought to have begun around Kyoto, and that it is said to have been prized by the aristocrats of Heian-kyo, the imperial capital (today’s Kyoto). From there it spread toward Aichi and Mie.

In Edo — the old name for Tokyo — udo became a pleasure for ordinary people. According to the city, cultivation of Tokyo udo began in the Edo period (from the 1600s), and it was one of the stylish delights of the Edo townsman, who loved hatsumono, the first produce of the season, much as he loved hatsugatsuo, the first bonito of early summer. There are not many vegetables that get mentioned in the same breath as first bonito. One is a fish that announces early summer from the sea; the other is a white stem that announces spring from the soil. The people of Edo, it seems, welcomed any herald of the season, wherever it came from.

Udo, I should mention, has to carry an unkind proverb. In Japanese, udo no taiboku — “a great tree of udo” — means someone who is big but good for nothing, because the plant grows tall and soft and its stalks are useless as timber. Saddled with that unflattering expression, udo went three metres underground and came back up as a gift. According to the Tokyo metropolitan guide, Tokyo udo is highly valued for its taste, used as a gift item and served in high-end ryotei restaurants. “Rising in the world” is a phrase invented for moments like this.

So by what route did this upwardly mobile white vegetable arrive in Tachikawa? The starting point was a surprising one.

From Kichijoji to Tachikawa, arriving after the silkworms

The Tokyo metropolitan guide says udo cultivation in western Tokyo is said to have begun in the late Edo period in the old village of Kichijoji — today’s Kichijoji in Musashino City, now one of the most fashionable neighbourhoods on the JR Chuo Line. The Ministry of Agriculture, Forestry and Fisheries, in its pages on regional home cooking, is a little more precise: udo cultivation began around Musashino Hachimangu Shrine from the 1830s, in the late Edo period onward. Given how busy Kichijoji is today, there is something funny about this. The former career of a town famous for its queues was udo farming.

The start date does vary a little from source to source. The metropolitan guide says the late Edo period, the ministry says the 1830s onward, and another metropolitan document introducing Edo-Tokyo vegetables says the cultivation method is said to have begun in Kichijoji in the final years of the shogunate. All of them end with “it is said.” The history of udo, too, seems to have gone a little underground.

After the Second World War, research into growing udo in pits moved forward. According to the ministry, research into “blanched udo” (nanka udo), grown in pits, was carried out from 1948, and the blanching method then spread across the Kitatama (North Tama) district. The city of Tachikawa writes that the technique reached Tachikawa by way of Musashino, Kodaira and Kokubunji. On the map, the know-how travelled from east to west, town to town.

Udo production in Tachikawa began in the decade after 1945, as silkworm raising declined, and full-scale production started in the decade from 1955. Udo was profitable and gave farmers precious income in winter, the off-season, and so its cultivation took off.

Reading that, I thought of Sunagawa. At Azusami Tenjin-sha Shrine (阿豆佐味天神社) in Sunagawa, there is Kokage Shrine (蚕影神社), dedicated to the god of silkworms, whose spirit was brought over from Hitachi Province (today’s Ibaraki Prefecture) at the end of the Edo period. The city writes that sericulture was so prosperous in Sunagawa that the villagers invited a guardian deity from distant Hitachi, and that it supported the village economy. After silk faded, udo arrived. Land that had grown silk on top of mulberry fields began to grow white stems underground. The land stayed the same; only what it grew was swapped out.

In the late 1940s and early 1950s, udo came to a village of mulberry trees. Full-scale production began in the decade from 1955, and from the decade beginning 1965 farmers started sending their root clumps to highlands such as Tochigi. At the peak, more than 80 farming households were climbing down into their pits every winter. A village that picked mulberry leaves in summer became a village that grew white stems in dark holes in winter. “A precious source of income in the winter off-season,” the city writes. When work in the fields stopped for winter, people got through it by working underground. I suspect there are still plenty of Tachikawa people who remember a muro in their grandparents’ field. How many remain today, we will count a little further on.

Udo that took root in Tachikawa like this has one more trait you cannot see from outside. It sleeps.

Waking the sleeping udo: the “Miyako” variety and gibberellin

Read a 2017 research report from the Tokyo Metropolitan Agriculture and Forestry Research Center, and you begin to understand what goes on in the darkness of an udo pit. According to the report, Tokyo’s pit-blanched udo has established itself as a branded vegetable known for its whiteness and juiciness, with about 300 tonnes a year produced, mainly in the Kitatama area. Production, however, has fallen to less than a tenth of its peak.

Udo varieties fall broadly into two groups: “spring udo,” which goes into deep dormancy, and “cold udo,” whose dormancy is shallow. Spring udo is better in flavour and shape, and almost all varieties used for blanching are spring udo, beginning with Miyako (都), the main variety in Tokyo.

And spring udo is hard to wake up. According to the report, it goes dormant from late autumn and only wakes after it has been exposed to winter cold in the field. Until around February it stays asleep, so even if the root clumps are bedded into the pit, the stems will not grow. Growers therefore break the dormancy with cold or with a plant hormone called gibberellin, and produce udo from late December to February.

So udo is bad at getting up in the morning, too. Even when you put it in a warm hole, it will not grow while it is still drowsy. I began to feel a certain kinship with udo. It was as if a plant had explained, from its own side, why I cannot get out of my futon on winter mornings.

The report says the usual harvest season is March to May, but forcing and retarding techniques have widened the season, so that Tokyo ships udo from the end of the year into summer. The thinnest period is October to mid-December, when the average market price is 507 yen — 1.2 times that of other periods. Waking the deeply sleeping udo in the season when it sells for the most: that was the problem growers and researchers had been working on.

The Miyako variety gives a high yield of around 900 grams per plant in ordinary cultivation, with root clumps bedded in March, and a stable share of top-grade produce of around 90 per cent. In the research, a cold-udo line called “Kohoku-kei 2,” obtained in 2008 from a grower in Shiga Prefecture, was crossed with Miyako to create offspring lines that sleep lightly. Kohoku-kei 2 barely goes dormant at all, but its stems are thin and it yields only around 200 grams per plant. The deep-sleeping star pupil and the small variety that drops off easily: the next generation of Tokyo udo has been entrusted to their children.

According to a metropolitan document reporting results of Tokyo’s agricultural research, the work has since narrowed the promising lines down to two and moved on to field trials. At the same time, researchers are developing a production system using cultured seedlings, which would do away with the heavy labour of raising and dividing root clumps, and DNA markers to protect new varieties. The work three metres underground leads all the way to the laboratory.

The same report includes observations of the udo flower. The flower is protandrous: the male parts ripen first and the female parts later, and the seventh day of flowering, during the female stage, is best for crossing. I will introduce later a Tachikawa character whose hair is modelled on udo flowers, but I had no idea those flowers kept such a punctual timetable.

Wake it from its sleep, let it grow long and white, carry it up to the surface. How much udo does Tachikawa produce this way today? The numbers turned out to be more honest than I expected.

Fifteen farms, 52 tonnes, number one in Tokyo

According to a table the city quotes from Tokyo’s official survey of agricultural production, Tachikawa was number one in Tokyo for the 2022 udo harvest: 463 ares planted, a harvest of 52 tonnes, 32.9 per cent of the Tokyo total. Second was Kokubunji with 36 tonnes; third, Kodaira with 21 tonnes. Kodaira, Kokubunji, Tachikawa — the route by which the technique once travelled west is traced exactly in reverse by today’s rankings.

The city, however, does not only list the flattering figures. Today, 15 households grow udo. At the peak, more than 80 farms produced over 500 tonnes, but with the rise of other growing regions and the lack of successors, production has fallen year after year. A TV programme that featured Tachikawa in April 2006 ranked Tokyo udo fifth among the city’s highlights, and its web page said Tachikawa was one of Japan’s leading udo regions, with about 30 farms growing it. In roughly twenty years, that number has halved. Eighty farms became 15. Five hundred tonnes became 52. And it is still number one in Tokyo — which also tells you how rare it has become to grow udo in Tokyo at all.

I cannot really picture 52 tonnes. But when I remember that every bit of it was carried up out of the dark three metres below, the number begins to weigh something. Somebody climbs down into a hole, checking the air with a candle flame, and brings the white stems up into the light, one at a time.

In fiscal 2006, as part of a project to promote the city’s specialities, Tachikawa created a brand of shorter udo called Tachikawa Komachi (立川こまち). It is Tokyo udo cut to a shorter standard length, and the city says it is easier to carry and more affordable. Indeed, boarding a train with a long stalk of udo in your arms would take some nerve. Put it on the luggage rack and you would forget it; hold it on your lap and it would brush the face of the person next to you. A very practical idea.

According to the Tokyo metropolitan guide, the Tachikawa Udo Producers’ Association has also developed its own packaging bag that blocks light and helps keep the quality. Udo that grew up avoiding the light underground goes on avoiding it after it reaches the shop. The effort to protect that whiteness continues after the harvest.

You can see the association in numbers, too. According to the city, the Tachikawa Udo Producers’ Association is a group of farmers who grow udo, and as of April 2024 it had 15 members. Besides direct sales in the city, it sells processed products made with Tachikawa udo at the agricultural festival and promotes Tachikawa Komachi. Fifteen farms, fifteen members. Each household’s face is, quite literally, the membership list.

Tokyo udo in numbers

• 3 — metres. The depth of an udo pit. Almost twice a person’s height, and some people go down into one every winter.
• 18–20 — degrees Celsius. The temperature inside the pit. Even in midwinter, it is shirtsleeve weather down there.
• About 1 — month. The time it takes the shoots from bedded root clumps to reach a length fit for shipping. Things grow fast underground.
• 52 — tonnes. Tachikawa’s 2022 harvest. About a third of Tokyo’s udo comes from Tachikawa.
• 15 — farms. The number growing udo in Tachikawa today. At the peak there were more than 80.
• 32 — entries. The number of exhibits at Tachikawa’s fiscal-2024 udo show. Five of them were the short Tachikawa Komachi.

A wayfarer’s quiz

Tachikawa Komachi, the brand the city created in fiscal 2006, changed which feature of Tokyo udo? (A) its colour, (B) its length, (C) where it is grown. The answer comes at the end.

That is enough numbers. Time to step into the kitchen. The whiteness that has been so carefully protected underground is put to the test the moment a knife goes in.