Tsuyu: A season that
shaped a culture
Meanwhile, as the whole of Asia begins to cook in the summer sun, a hot air mass develops over the continent, setting off a vast northeastward migration of air along the East Asian coastline. The flow encounters a burgeoning accumulation of damp air centered off Micronesia, helping to draw it toward the continent.
There is conflict in the heavens: The warm air wants to spread out, but the cold air puts up resistance. The two titans clash.
Any resident of the region knows what happens next. Water vapor in the wet air mass condenses, and the result is weeks and weeks of cloud and rain over Japan, eastern China and South Korea -- the period of East Asia's weather cycle known in Japanese as tsuyu. This year, the umbrellas came out on May 10 in Okinawa, fully a month before the rains came to Shikoku, Kyushu and Honshu last week. Hokkaido has no distinct tsuyu season.
Irksome it may be, but the monthlong summer rain is what gives Japan's forests and gardens their lushness. Without it, hydrangeas and irises would not be the seasonal splendors they are. Indeed, the name tsuyu itself signifies fruition: The Chinese characters used to write it are those for "plum" (or, more accurately, "Japanese apricot") and "rain" -- a pairing probably chosen because tsuyu arrives just as the succulent fruits are ripening. And were it not for tsuyu, the rice cultivation that is the basis of Japan's culture and psyche would not be possible.
"People have to be strong to plant rice stalks one by one or to yank weeds in the sweltering heat of summer. They band together," said Yoshio Masuda, professor emeritus of cultural anthropology at the University of Tokyo. Despite mechanization taking much of the toil out of farming, that spirit hasn't died out in Japanese society, he said. "Collectivism is still very much alive today. It's a cultural characteristic."
And yet tsuyu is the cause of much discontent. A fine mist hangs in the air, seeming never to lift, and clothes stick to the skin. The warmth and high humidity aid mildew's and mold's attempts to colonize the nation's bathroom walls. "It drives me nuts," says 53-year-old Tokyo housewife Sachiko Osumi.
To battle the elements, Osumi -- like countless other homemakers across the country -- every year implements a natsu taisaku, or "summer action plan." To keep futons from going musty in the closet, she stores them on wooden platforms that allow air to flow through below. She also spreads rattan matting across the living-room floor, so that when her family of five recline it's cool and dry to the touch. "Just some tricks my parents taught me," she explains.
Housewives who take a more aggressive, less-traditional tack can choose from a bewildering array of high-tech natsu-taisaku products available everywhere. One major retailer stocks 25 anti-mildew agents, 38 kitchen products to prevent food poisoning -- on the rise during tsuyu -- and 68 gizmos to absorb moisture from shoes and clothes.
It is no overreaction. Japan's 1,714-mm average annual precipitation -- including that from autumn's typhoons and the all-engulfing snow of Tohoku and Hokkaido winters -- is nearly twice the global average of 973 mm, according to figures from the Land Ministry. Japan ranks behind only Indonesia, the world's wettest country, New Zealand and the Philippines in the amount of water dumped on it from the sky.
Considering this, it's hardly surprising that the Japanese language is rich in evocative terminology for rain. Examples include onuke (big coming-out), which connotes a torrential downpour, and aoba ame (green-leaf rain), which describes raindrops that complement the beauty of new foliage. And that's only a tiny selection of some hundreds of names for various forms of rain -- with more than a dozen to describe subtle differences in tsuyu alone.
In the countryside, naturally enough, a rich body of weather-related sayings have long been passed down by generations of farmers who looked to the sky for clues on when to plant or harvest. Summer rain is, of course, a common theme. "A tsuyu that begins with thunder won't be wet," goes one. "A tsuyu with light rain yields a good crop," declares another.
Daigo Yoshiyasu, a former official at the Japan Meteorological Agency, was so impressed by such adages that he compiled them into a book published in 1984, in the forward of which he observes that ancient weather wisdoms were sometimes accurate even when the most advanced forecasting models failed.
With so much rain pitter-pattering through the eons, no page in the annals of these islands has stayed completely dry. And besides being key to Japan's agrarian development, tsuyu has played its part in its history, too.
In perhaps the most dramatic episode, in 1582 the feudal warlord Hideyoshi Toyotomi diverted water from the Ashimorigawa River, which was swollen by tsuyu rains, to flood Takamatsu Castle in present-day Okayama Prefecture. With much of the low-lying fortress inundated, it was impossible for his enemy within the walls to light fires to cook what little food had survived the deluge. The defenders went hungry and eventually surrendered, handing Hideyoshi a victory that set him on course to taking military control of the country and building a foundation for national unity.
More recently, during the cataclysmic Battle of Okinawa in 1945, tsuyu clouds benefited the retreating Japanese forces by giving them two days of cover from U.S. aerial surveillance, said military analyst Tadasu Kumagai. Meanwhile, he added, mud immobilized the enemy's tanks, so delaying the eventual conquest.
However, perhaps the most crucial intervention by weather in Japanese military history -- although not caused by tsuyu -- was that by the kamikaze, or "divine wind," whose storms twice scattered and sank invading Mongol armadas off northwestern Kyushu, in 1274 and 1281. In World War II, as everyone knows, the term was used for the suicide pilots who attacked Allied ships.
Art and literature, too, have felt the clammy touch of tsuyu. In Murasaki Shikibu's 11th-century classic, "The Tale of Genji," summer rains put young male characters in the mood for romance -- an emotion that Japanese in the Heian Period (794-1185) considered just another affliction of the summer months, said professor of comparative literature Susumu Nakanishi. "Tsuyu," he wryly observed, "was the time when love sprouted -- like mildew."
The famed ukiyo-e artist Utagawa Hiroshige appears to have been oppressed by thoughts of summer rains. In his 1857 woodblock print titled "Great Bridge, Sudden Shower at Atake," a maleficent cloud unleashes masterfully wrought streaks of rain on pedestrians caught out on the bridge, and an oarsman working the Sumida River below it. The sky is a murky shade of gray, perhaps suggestive of the people's sodden spirits.
Fast-forwarding to Japanese cinema, we find that here, too, rain often highlights key dramatic moments, as in the opening scene of Akira Kurosawa's 1950 film "Rashomon," in which a curtain of water pelts three figures huddled under a Kyoto city gate. In the 1987 comedy "Tampopo," directed by Juzo Itami, a gangster shot through with bullets bids farewell to his cloying girlfriend as rain pours from the firmament.
The erratic nature of the rainy season in recent years has done nothing to improve its poor reputation. In the past decade, there has been a rise in sudden, summer-evening thunderstorms accompanied by intense downpours, reportedly due to a "heat-island" effect as domes of high-temperature air rise above extensively concreted and asphalted conurbations such as those around Tokyo and Osaka-Kobe.
Until now, Japan has been making do with subway-size tunnels designed to channel water from massive rainfalls of up to 50 mm per hour, but some of the worst new storms deliver almost twice that. Residential flooding, once mainly the bane of rural regions, has increasingly become an urban blight. "Local governments can't lay new pipes fast enough to keep up," says Seiichiro Okamoto, an official at the Land Ministry's waste water management division.
Though Japan's rainfall is generous by most measures, because so many people are packed into the country's relatively small area, the per capita water resources (5,200 cu. meters) is only one-fourth the world average. That means the nation needs every drop it gets.
Some years, though, when the air pressure of the wet air mass coming in from Micronesia is stronger than that of its northern rival, the rain front -- and tsuyu -- is pushed too far north to affect Japan's main islands -- a weather condition popularly known as karatsuyu, or "empty rainy season."
Something along these lines happened last year, when scant rainfall and record-breaking temperatures prompted authorities in several areas to order water intake by homes and businesses to be slashed. The central government warned that the Kanto and Chubu areas would possibly suffer their worst water shortages in years. In the end, only typhoon rains spared those regions a severe drought.
For the rice farmers who feed Japan, any extreme in weather is bad news. "If there's no rain, the crops wither. If there's not enough sun, they don't dry sufficiently and get diseased. Output falls by as much as half," explained Kanae Takeda, a rice farmer in Niigata Prefecture, where some of the tastiest varieties of the staple grow. "No rain is trouble and too much rain is trouble."
The temperamental showers of summer always provoke strong commentary from the Japanese, for whom they are a fundamental part of life. They may see it as the root of their culture and an agricultural necessity. Some merely call it a domestic inconvenience. But nobody denies that the character of the people is shaped by the drops that fall on them from cloudy skies.
"Japan is a country of rain," said Nakanishi, the professor of literature. "The drizzling in the spring makes people wet and spirits begin to sink. Then in the autumn-winter period there's more rain and it too brings on unusual emotions. Our hearts get carried away -- and it's all because of the rain."
The Japan Times: June 16, 2002
This story originally appeared in a Japan Times package on tsuyu rain: