Portuguese missionaries brought bread to Japan in 1543, and today it’s more popular than rice

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Certain foods seem inextricably linked to their countries of origin: think pasta in Italy, curry in India, teff in Ethiopia, baguettes in France, rice in China. Say Japan, and you probably conjure sushi, sashimi, yakitori. But bread? Not so much.

Brace yourself. Bread consumption in Japan has risen faster than a yeast-laden loaf. In 2011, the Japanese spent more on bread than they did on the more tradition-seeming staple rice.

It wasn’t always so. Bread first landed on Japanese soil along with the first Europeans, Portuguese traders, in 1543. Subsequent ships came bearing missionaries, weaponry, and unusual food, namely bread and wheat. The Portuguese, who looked, smelled, and sounded so different, were called “Southern barbarians.” But the Japanese, in the midst of a civil war, tolerated the outsiders for a time because they were keen to purchase Portuguese firearms.

That tolerance ended, and the last of the Portuguese missionaries were banished from the island in 1639, but before they left, they traveled inland trying to convert more Japanese to Catholicism. (The missionaries were remarkably successful, which is what got them banned. Historians estimate there were 500,000 converted Catholics in Japan.) They carried with them their unusual foodstuff, that is, bread. Interestingly, the Portuguese Catholics also introduced to Japan the concept of batter-frying food coated in wheat. Today tempura seems as synonymous with Japanese cuisine as sushi.

With the Sakoku edict of 1635, Japan famously closed its borders to outsiders, becoming an insular and isolated country. For more than two centuries, trade was severely restricted and nearly all foreigners were prohibited from entering the country.

Most Japanese lived on rice, millet, and barley, supplemented with vegetables and the occasional bit of fish.

Bread fell off the Japanese table until the Opium War in 1840, when it was mass-produced as a convenient field ration to feed hungry soldiers, under the recommendation of a military science researcher, according to LiveJapan.com.

Even among the military, bread was not universally admired. When the Japanese Navy tried to introduce Western-style bread and a dry wheat cracker called kanpan in 1890, the servicemen went on strike, according to Slate magazine.

With its borders opened to the rest of the world by the late 1800s, bread and other wheat products came back to Japanese menus, though in limited quantities. Working-class laborers ate wheat udon noodles; aspiring middle-class salarymen went to Western-style cafes, where they sampled unusual treats like pastries, cakes, and anpan, a sweet cake filled with black bean fudge.

During World War II, rice was reserved for soldiers. Civilians subsisted on rations of crude bread, dumplings, kanpan, and udon noodles. The situation got worse after the war, and Japan was on the brink of starvation when the U.S. sent in emergency rations of wheat and lard. As they already were in the U.S., sandwiches became a staple in subsidized school lunches in urban areas, a practice that lasted until the 1970s and that normalized sandwiches as a part of daily lives.

“In demographic terms, the reason the Japanese diet has shifted so markedly toward bread consumption in recent years is that those who have grown up with bread as part of their everyday diet now constitute a majority of the population,” as Iwamura Nobuko recounted on Nippon.com.

The Japanese government encouraged a Western diet of bread, meat, and dairy products in the 1950s and 1960s, according to Nobuko, as a way to build strong bodies, and set up policies to encourage wheat farming. Bread soon became emblematic of a trendy Western lifestyle.

Today in Japan, as in other parts of the industrial world, contemporary busy families are dependent on quick, portable, individual meals with easy cleanup. Rice traditionally requires the preparation of at least three side dishes; a bread sandwich is easier to prepare and to customize for various family members’ tastes.

Between slices of bread, however, you’ll find something more indigenous than ham and cheese. Popular Japanese sandwiches include Yakisoba Pan, with fried soba noodles and pickled ginger; a Toyko favorite called Katsu Sando, deep-fried pork, with pickled cabbage and barbecue sauce; and Kurama, a fruit and cream filled dessert sandwich. Yum! What’s for lunch?

 E.L. Hamilton

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Spice: Why some of us like it hot

Piles of spices in market (Credit: Getty Images)

Human beings around the world delight in fiery foods. Thai, Mexican, Chinese, Indian, Ethiopian – the cuisines that can take the roof off your mouth are numerous and flavourful.

Ranking the world’s most spicy peppers and comparing the most awe-inducing dishes is a common pastime, even if, past a certain point, the distinctions are somewhat moot. Who can say, subjectively speaking, that one Indian restaurant’s Widower Phaal, made while wearing goggles with chilis that rank about 1,000,000 on the Scoville Scale – an international measurement of pungency – is necessarily a fierier experience than the notorious Korean Suicide Burrito?

There’s plenty of burn to go around: more common dishes include vindaloo with ghost peppers and hot pot from Sichuan, where you must part a swarm of chillis bobbing in a sea of broth to fish out tender, fiery morsels of meats and vegetables.

As you savour these intense tastes, however, you may wonder, why do some cuisines compete for the title of spicy champion, while others feature barely the hint of a burn?

This is a question that has intrigued anthropologists and food historians for some time. Indeed, it’s a curious truth that places with warm climates do seem to have a heavier preponderance of hot and spicy dishes. That may have something to do with the fact that some spices have antimicrobial properties, studies have found.

Chilli pepper and powder (Credit: Getty Images)

Chillis pack fierce heat but also antimicrobial agents that could have been useful in the days before refrigeration (Credit: Getty Images)

In one survey of cookbooks from around the world, researchers note: “As mean annual temperatures (an indicator of relative spoilage rates of unrefrigerated foods) increased, the proportion of recipes containing spices, number of spices per recipe, total number of spices used, and use of the most potent antibacterial spices all increased.” In hot places, where before refrigeration food would have gone off very quickly, spices might have helped things keep a bit longer – or at least rendered them more palatable.

It’s also been suggested that because spicy food makes most people sweat, it might help us to cool off in hot parts of the world. The evaporative cooling effect that happens when we perspire is indeed useful in maintaining a body’s heat balance. In a very humid climate, though, it doesn’t matter how much you sweat: that evaporation won’t come to your rescue because there’s already too much moisture in the air. One study of people who drank hot water after exercise showed that they did cool down slightly more than those who drank cold water, but only in situations with low humidity. Thailand in August, that ain’t.

But spice is hardly limited to the tropics. While chilli peppers are originally from the Americas, this particular kind of heat grew widespread in the 15th and 16th Centuries, travelling with European traders. Other spices – not spicy in the same way as peppers, perhaps, but still strongly flavoured and bringing an extra oomph to a dish – had been circulating in Europe for centuries, with ginger, black pepper, and cinnamon brought in from the east.

As spice prices plummeted in Europe in the 1600s, and it became easier for just anyone to lace their food with them, tastemakers fell out of love with them

Heavily spiced dishes were the darlings of many cuisines we currently don’t think of for their zing. Numerous recipes in one 18th-Century British cookery book include potent doses of mace, cloves, and nutmeg, for instance. What happened?

Well, one possibility is that it became a bit uncouth to like quite so many flavours in one’s food, as Maanvi Singh has written over at The Salt. What we now consider classic European cuisine has a tendency to focus on pairing like flavours with like, rather than bringing in a riot of strong, contrasting ones. That may be because, as spice prices plummeted in Europe in the 1600s and it became easier for just anyone to lace their food with them, tastemakers fell out of love with them.

Shifting the goalposts for high-end food, they began to emphasise dishes where the focus was the purest essence of the basic ingredients, combined with flavours that served to bring that out. In a word – it may have been snobbery, Singh writes, that erased the thrill of spice from many European palates.

Nutmeg (Credit: Getty Images)

Many European cuisines used to be heavily spiced with ingredients such as nutmeg (Credit: Getty Images)

Indeed, the role of human culture in determining whether spice is hot or not cannot be underestimated. Like all animals, we use taste as a way to determine what’s safe to eat, and once we get used to certain flavors signalling the familiar, we like them all the more. It would not be surprising if some people, having acclimated to chillis, began to prefer them over the absence of chillis.

Today, we have our own reasons for eating spicy foods, and they may have more to do with adrenaline than social status or sheer flavour, per se. The physiological reaction to peppers, as we’ve discussed here before, is the result of temperature sensors in the mouth being activated. Your body responds as if you had burned it, causing you to sweat and flush, and in extreme cases vomit.

The thrill of triggering this intense experience without (usually) any long-term effects is thought to be part of the attraction – as well as, for some chilli fiends, the bragging rights.

Antimicrobial qualities and body temperature regulation are probably not on the list of possible draws today – something to ponder, and thank your lucky stars for, as you wait for your next curry.

The People of Ellis Island- Portraits of immigrants arriving in the U.S.A from the early 1900’s

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Ellis Island was the gateway for millions of immigrants to the United States as the nation’s busiest immigrant inspection station from 1892 until 1954. Between 1905 and 1914, an average of one million immigrants per year arrived in the United States.

Immigration officials reviewed about 5,000 immigrants per day during peak times at Ellis Island.Two-thirds of those individuals emigrated from eastern, southern and central Europe. The peak year for immigration at Ellis Island was 1907, with 1,004,756 immigrants processed.

The all-time daily high occurred on April 17, 1907, when 11,747 immigrants arrived. After the Immigration Act of 1924 was passed, which greatly restricted immigration and allowed processing at overseas embassies, the only immigrants to pass through the station were those who had problems with their immigration paperwork, displaced persons, and war refugees.

Today, over 100 million Americans—about one-third of the population—can trace their ancestry to the immigrants who first arrived in America at Ellis Island before dispersing to points all over the country. Here are some photos of immigrants from the early 1900’s. All photos by  New York Public Library

A Bavarian man

 

A Danish man

A Dutch woman

 

A Greek Orthodox priest

 

A Greek woman

A Guadeloupean woman

 

A man whose descent was not identified, possibly Russian

 

A Romanian man

 

A Ruthenian woman

 

A Slovak woman with her child

During World War I, the German sabotage of the Black Tom Wharf ammunition depot damaged buildings on Ellis Island. The repairs included the current barrel-vaulted ceiling of the Main Hall.

During and immediately following World War II, Ellis Island was used to intern German merchant mariners and “enemy aliens”—Axis nationals detained for fear of spying, sabotage, and other fifth column activity.

In December 1941, Ellis Island held 279 Japanese, 248 Germans, and 81 Italians removed from the East Coast. Unlike other wartime immigration detention stations, Ellis Island was designated as a permanent holding facility and was used to hold foreign nationals throughout the war.A total of 7,000 Germans, Italians and Japanese would be ultimately detained at Ellis Island. It was also a processing center for returning sick or wounded U.S. soldiers, and a Coast Guard training base.

 

An Albanian soldier

 

An Indian boy

 

An Italian woman

 

Another man whose descent was not identified, possibly Russian

 

Several Romani people

 

Several Romani people

 

Three Dutch women

 

Three Russian Cossacks

 

Three Scottish boys

 

Two Romanian women

Generally, those immigrants who were approved spent from two to five hours at Ellis Island. Arrivals were asked 29 questions including name, occupation, and the amount of money carried.

It was important to the American government that the new arrivals could support themselves and have money to get started. The average the government wanted the immigrants to have was between 18 and 25 dollars. Those with visible health problems or diseases were sent home or held in the island’s hospital facilities for long periods of time.

More than three thousand would-be immigrants died on Ellis Island while being held in the hospital facilities. Some unskilled workers were rejected because they were considered “likely to become a public charge.” About 2 percent were denied admission to the U.S. and sent back to their countries of origin for reasons such as having a chronic contagious disease, criminal background, or insanity.

Ellis Island was sometimes known as “The Island of Tears” or “Heartbreak Island”because of those 2% who were not admitted after the long transatlantic voyage. The Kissing Post is a wooden column outside the Registry Room, where new arrivals were greeted by their relatives and friends, typically with tears, hugs and kisses.

https://www.thevintagenews.com/2018/02/25/the-people-of-ellis-island/

This is the oldest surviving melody dating back to 1400 BC

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The Hurrian songs are a group of stone tablets with music inscribed in the cuneiform writing system. These were unearthed from the ancient Amorite city of Ugarit and date to approximately 1400 BC.

One of these tablets (h.6), contains the Hurrian hymn to Nikkal, making it the earliest markedly entire piece of composed music in the world. On some of the broken pieces, the composers’ names are inscribed, but h.6 is an anonymous work.

H.6 is one of about 36 such hymns in ancient Sumerian writing, and it’s the only one that remained in a substantially complete form. The other hymns were found on fragments of stone tablets, unearthed in the 1950s from present-day Ras Shamra, Syria, on the site of the ancient Royal Palace at Ugarit. They were discovered in a layer of earth dating from the 14th century BC. An account of the group of hymns was published in 1955 and 1968 by Emmanuel Laroche, who cataloged all of the song tablets with the designation ‘h’ for “Hurrian.” The entire hymn is identified as h.6 in the list; it was revised and published in 1975.

The lyrics of the h.6 tablet are a hymn to Nikkal, a Semitic goddess of orchards. It also contains inscribed directions for a singer playing a nine-stringed sammûm, a type of harp or, more likely, a lyre. Instructions for how to tune the harp are also contained on some of the tablets.

Several other survived early works of music, such as the Seikilos epitaph and the Delphic Hymns, are pre-dated by the Hurrian hymn by nearly a thousand years, but the Hurrian transcription remains contentious. A reconstruction of the lyrics by Marcelle Duchesne-Guillemin may be heard at the Urkesh web page, though this is only one of at least five differing interpretations of the wording, and each one bears an entirely remarkable result.

The composition of the h.6 tablet assigns the Hurrian words of the hymn on the top of the tablet, under which lies a paired division line. The hymn text is written in a continuous spiral, alternating between the front and back sides of the tablet – a layout not found in Babylonian texts. Below this text, there are Akkadian musical instructions, comprised of separated names followed by number signs. The differences in transcriptions focus on the interpretation of the meaning of these paired number signs and the association to the hymn text.

Below the musical instructions, there is another dividing line, a single one, underneath which there is an imprint in Akkadian which reads, “this nitkibli [i.e., the nid qabli tuning] song, a zaluzi to the gods… written down by Ammurabi”. This name, along with another scribe’s name, Ipsali, found on one of the other tablets, is Semitic.

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There is no songwriter signed for the complete h.6 hymn, but four composer names, which are all Hurrian, are found on five of the other fragmentary pieces

The tablet is now part of a collection at the National Museum of Damascus.

Roopkund is a lake in India famous for the mysterious ancient skeletons that float in its waters

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It is rather unnerving to stand over a lake and see a huge pile of skulls and bones tangled up under the water’s surface. You’re left wondering who are they, and most importantly how they got here in the first place, for this lake is 16,000 feet above sea level with nothing but ice peaks and frozen glaciers surrounding it.

This frozen, shallow lake, tucked away deep in the Indian Himalayas, offers such a sight every year when the ice melts and reveals the human remains of more than 300 unfortunate individuals who rest at the bottom of Roopkund, better known as Skeleton Lake.

This “splendid” view is available to any trekking enthusiast who would dare to walk the steep route that climbs out from the heart of Lohajung’s dark forest in Uttarakhand, India, and pursue the five-day trekking adventure up to the glacial lake that sits frozen for most of the time in a small valley high up in the Garhwal part of the Himalayas.

However, for one month, when the temperature is friendly enough, the ice starts to melt and the surface starts to be see-through. Then, the bottom of the lake that is six feet at its deepest point shows what lies beneath this small and seemingly typical natural wonder. It’s a death pit full of skeletons and not just that, but hair, nails, spears, knives, and jewelry, preserved by the frost as if it was only a few years since these souls met their demise and mysteriously found their way to the bottom of this lake.

Scientists, anthropologists, and historians have tried to unravel this mind-boggling mystery. In 1942, when the lake’s contents was first discovered by a British forest ranger, they were believed to be recent humans remains of unfortunate Japanese soldiers passing through the mountains. The ranger stumbled on a human skull peeking through the snow just outside of the lake, so based on how it was preserved with a full set of hair, he simply assumed the most likely scenario. When he shortly found more bones nearby and skeletons below the frozen surface of the lake, he filed a report.

 And at first his assumptions seemed logical. But no investigation was made about the bones and no one knew who they were, how long they had been there, nor what had happened for that matter. So clearly, in times when a war was still raging, the authorities shared the same initial belief that these were the remains of a military battalion passing by through the mountains toward India. But after a more thorough investigation on site, when spears and all kinds of different ancient weapons and trinkets were found lying right next to the bones, all those first impressions went down the drain and it was clear that a full study of the remains needed to be done.

For a time, the mystery remained unsolved and many theories about what had happened were set in motion. Landslides, epidemic, and ritual suicides were only a few of them. People even went as far as to accept a local belief about an ancient goddess laying waste to a group of people who defied her. According to the legend, this goddess was so infuriated by a group of travelers who dared to pass and tarnish her intact sanctuary up in the mountains that she flung iron-like hailstones over these petty disrespectful humans, killing them on the spot.

Which was actually not so far from the truth, for recent studies found clear marks of round-shaped blows to the skulls and their shoulders as if they were struck from above.

An expedition led by a team of Indian scientists with a couple of Europeans went to the lake in 2004  in order to take samples and investigate. With the advancement of DNA testing, it was now possible to examine the bones and some of the preserved human tissue. The popular opinion was that the skeletons were the remains of individuals who died from harsh weather and sudden storms over the years on the mountains and slid with the snow into the lake, which prevented the natural process of decomposition.

However, while they found the bodies differentiated in terms of height and body type, the Oxford University Radiocarbon Accelerator Unit in the United Kingdom found almost all of the remains to be from the same time, around 850 A.D. Moreover, they found two distinct body types with similar DNA. One group of shorter individuals with smaller and thinner bones, and one completely the opposite. Which led them to believe that it must have been a group on pilgrimage or some kind of expedition in the mountains that hired some local guides. Unfortunately for them, trapped in a valley and with shelter nowhere to be found, a baseball-size hail storm killed them on their way. At least, that is according to the latest scientific research.

According to the traditional Himalayan legend of the ancient goddess, a king was traveling with his pregnant wife, his family, their servants, his musicians, and several others who wished to join them on a pilgrimage to the Uttarakhand’s Nanda Devi Raj Jat festival in India that only happen once every 12 years.

They hired locals to help them get there, but along the way, and despite locals telling them otherwise, they angered the goddess Nanda Devi with their loudness and were punished for it. But most of all, within the group there was a pregnant woman who allegedly gave birth on the goddess’s sacred land. According to local customs, a newborn was the greatest sin of all, so she sent out a storm of hailstones “hard as iron” and killed them.

While we don’t believe this was the wrath of a goddess, it certainly was the fury of something that killed these hundreds of people.

A legend at least in part explained the mystery long before science did. That is, until further notice and more investigation shows something entirely different. A scientific or academic institution should pursue this, for unfortunately every trekking passer-by picks up a bone or two as a souvenir, and very shortly there might be nothing left to be studied.

 Brad Smithfield

Why Do We Need to Sleep?

An illustration of animals sleeping while researchers inspect them

At a shiny new lab in Japan, an international team of scientists is trying to figure out what puts us under.

TSUKUBA, JapanOutside the International Institute for Integrative Sleep Medicine, the heavy fragrance of sweet Osmanthus trees fills the air, and big golden spiders string their webs among the bushes. Two men in hard hats next to the main doors mutter quietly as they measure a space and apply adhesive to the slate-colored wall. The building is so new that they are still putting up the signs.

The institute is five years old, its building still younger, but already it has attracted some 120 researchers from fields as diverse as pulmonology and chemistry and countries ranging from Switzerland to China. An hour north of Tokyo at the University of Tsukuba, with funding from the Japanese government and other sources, the institute’s director, Masashi Yanagisawa, has created a place to study the basic biology of sleep, rather than, as is more common, the causes and treatment of sleep problems in people. Full of rooms of gleaming equipment, quiet chambers where mice slumber, and a series of airy work spaces united by a spiraling staircase, it’s a place where tremendous resources are focused on the question of why, exactly, living things sleep.

Ask researchers this question, and listen as, like clockwork, a sense of awe and frustration creeps into their voices. In a way, it’s startling how universal sleep is: In the midst of the hurried scramble for survival, across eons of bloodshed and death and flight, uncountable millions of living things have laid themselves down for a nice, long bout of unconsciousness. This hardly seems conducive to living to fight another day. “It’s crazy, but there you are,” says Tarja Porkka-Heiskanen of the University of Helsinki, a leading sleep biologist. That such a risky habit is so common, and so persistent, suggests that whatever is happening is of the utmost importance. Whatever sleep gives to the sleeper is worth tempting death over and over again, for a lifetime.

The precise benefits of sleep are still mysterious, and for many biologists, the unknowns are transfixing. One rainy evening in Tsukuba, a group of institute scientists gathered at an izakaya bar manage to hold off only half an hour before sleep is once again the focus of their conversation. Even simple jellyfish have to rest longer after being forced to stay up, one researcher marvels, referring to a new paper where the little creatures were nudged repeatedly with jets of water to keep them from drifting off. And the work on pigeons—have you read the work on pigeons? another asks. There is something fascinating going on there, the researchers agree. On the table, dishes of vegetable and seafood tempura sit cooling, forgotten in the face of these enigmas.

Biologists call this need “sleep pressure”: Stay up too late, build up sleep pressure. Feeling drowsy in the evenings? Of course you are—by being awake all day, you’ve been generating sleep pressure! But like “dark matter,” this is a name for something whose nature we do not yet understand. The more time you spend thinking about sleep pressure, the more it seems like a riddle game out of Tolkien: What builds up over the course of wakefulness, and disperses during sleep? Is it a timer? A molecule that accrues every day and needs to be flushed away? What is this metaphorical tally of hours, locked in some chamber of the brain, waiting to be wiped clean every night?

In other words, asks Yanagisawa, as he reflects in his spare, sunlit office at the institute, “What is the physical substrate of sleepiness?”

Biological research into sleep pressure began more than a century ago. In some of the most famous experiments, a French scientist kept dogs awake for more than 10 days. Then, he siphoned fluid from the animals’ brains, and injected it into the brains of normal, well-rested canines, which promptly fell asleep. There was something in the fluid, accumulating during sleep deprivation, that made the dogs go under. The hunt was on for this ingredient—Morpheus’s little helper, the finger on the light switch. Surely, the identity of this hypnotoxin, as the French researcher called it, would reveal why animals grow drowsy.

In the first half of the 20th century, other researchers began to tape electrodes to the scalps of human subjects, trying to peer within the skull at the sleeping brain. Using electroencephalographs, or EEGs, they discovered that, far from being turned off, the brain has a clear routine during the night’s sleep. As the eyes close and breathing deepens, the tense, furious scribble of the waking mind on the EEG shifts, morphing into the curiously long, loping waves of early sleep. About 35 to 40 minutes in, the metabolism has slowed, the breathing is even, and the sleeper is no longer easy to wake. Then, after a certain amount of time has passed, the brain seems to flip a switch and the waves grow small and tight again: This is rapid eye movement, or REM, sleep, when we dream. (One of the first researchers to study REM found that by watching the movements of the eyes beneath the lids, he could predict when infants would wake—a party trick that fascinated their mothers.) Humans repeat this cycle over and over, finally waking at the end of a bout of REM, minds full of fish with wings and songs whose tunes they can’t remember.

Sleep pressure changes these brain waves. The more sleep-deprived the subject, the bigger the waves during slow-wave sleep, before REM. This phenomenon has been observed in about as many creatures as have been fitted with electrodes and kept awake past their bedtimes, including birds, seals, cats, hamsters, and dolphins.

If you needed more proof that sleep, with its peculiar many-staged structure and tendency to fill your mind with nonsense, isn’t some passive, energy-saving state, consider that golden hamsters have been observed waking up from bouts of hibernation—in order to nap. Whatever they’re getting from sleep, it’s not available to them while they’re hibernating. Even though they have slowed down nearly every process in their body, sleep pressure still builds up. “What I want to know is, what about this brain activity is so important?” says Kasper Vogt, one of the researchers gathered at the new institute at Tsukuba. He gestures at his screen, showing data on the firing of neurons in sleeping mice. “What is so important that you risk being eaten, not eating yourself, procreation … you give all that up, for this?

The search for the hypnotoxin was not unsuccessful. There are a handful of substances clearly demonstrated to cause sleep—including a molecule called adenosine, which appears to build up in certain parts of the brains of waking rats, then drain away during slumber. Adenosine is particularly interesting because it is adenosine receptors that caffeine seems to work on. When caffeine binds to them, adenosine can’t, which contributes to coffee’s anti-drowsiness powers. But work on hypnotoxins has not fully explained how the body keeps track of sleep pressure.

For instance, if adenosine puts us under at the moment of transition from wakefulness to sleep, where does it come from? “Nobody knows,” remarks Michael Lazarus, a researcher at the institute who studies adenosine. Some people say it’s coming from neurons, some say it’s another class of brain cells. But there isn’t a consensus. At any rate, “this isn’t about storage,” says Yanagisawa. In other words, these substances themselves don’t seem to store information about sleep pressure. They are just a response to it.

Sleep-inducing substances may come from the process of making new connections between neurons. Chiara Cirelli and Giulio Tononi, sleep researchers at the University of Wisconsin, suggest that since making these connections, or synapses, is what our brains do when we are awake, maybe what they do during sleep is scale back the unimportant ones, removing the memories or images that don’t fit with the others, or don’t need to be used to make sense of the world. “Sleep is a way of getting rid of the memories in a way that is good for the brain,” Tononi speculates. Another group has discovered a protein that enters little-used synapses to cause their destruction, and one of the times it can do this is when adenosine levels are high. Maybe sleep is when this cleanup happens.

There are still many unknowns about how this would work, and researchers are working many other angles in the quest to get to the bottom of sleep pressure and sleep. One group at the Tsukuba institute, led by Yu Hayashi, is destroying a select group of brain cells in mice, a procedure that can have surprising effects. Depriving mice specifically of REM sleep by shaking them awake repeatedly just as they’re about to enter it (a bit like what happens to the parents of crying babies) causes serious REM sleep pressure, which mice have to make up for in their next bout of slumber. But without this specific set of cells, mice can miss REM sleep without needing to sleep more later. Whether the mice get away totally unscathed is another question—the team is testing how REM sleep affects their performance on cognitive tests—but this experiment suggests that where dreaming sleep is concerned, these cells, or some circuit they are part of, may keep the records of sleep pressure.

Yanagisawa himself has always had a taste for epic projects, like screening thousands of proteins and cellular receptors to see what they do. In fact, one such project brought him into sleep science about 20 years ago. He and his collaborators, after discovering a neurotransmitter they named orexin, realized that the reason the mice without it kept collapsing all the time was that they were falling asleep. That neurotransmitter turned out to be missing in people with narcolepsy, who are incapable of making it, an insight that helped trigger an explosion of research into the condition’s underpinnings. In fact, a group of chemists at the institute at Tsukuba is collaborating with a drug company in an investigation of the potential of orexin mimics for treatment.

These days, Yanagisawa and collaborators are working on a vast screening project aimed at identifying the genes related to sleep. Each mouse in the project, exposed to a substance that causes mutations and fitted with its own EEG sensors, curls up in a nest of wood chips and gives in to sleep pressure while machines record its brain waves. More than 8,000 mice so far have slumbered under observation.

When a mouse sleeps oddly—when it wakes up a lot, or sleeps too long—the researchers dig into its genome. If there is a mutation that might be the cause, they try to engineer mice that carry it, and then study why it is the mutation disrupts sleep. Many very accomplished researchers have been doing this for years in organisms like fruit flies, making great progress. But the benefit to doing it in mice, which are extremely expensive to maintain compared to flies, is that they can be hooked up to an EEG, just like a person.

A few years ago, the group discovered a mouse that just could not seem to get rid of its sleep pressure. Its EEGs suggested it lived a life of snoozy exhaustion, and mice that had been engineered to carry its mutation showed the same symptoms. “This mutant has more high-amplitude sleep waves than normal. It’s always sleep-deprived,” says Yanagisawa. The mutation was in a gene called SIK3. The longer the mutants stay awake, the more chemical tags the SIK3 protein accumulates. The researchers published their discovery of the SIK3 mutants, as well as another sleep mutant, in Nature in 2016.

While it isn’t exactly clear yet how SIK3 relates to sleepiness, the fact that tags build up on the enzyme, like grains of sand pouring to the bottom of an hourglass, has the researchers excited. “We are convinced, for ourselves, that SIK3 is one of the central players,” says Yanagisawa.

As researchers probe outward into the mysterious darkness of sleepiness, these discoveries shine ahead of them like flashlight beams, lighting the way. How they all connect, how they may come together into a bigger picture, is still unclear.

The researchers hold out hope that clarity will come, maybe not next year or the next, but sometime, sooner than you might think. On an upper story at the International Institute for Integrative Sleep, mice go about their business, waking and dreaming, in row after row of plastic bins. In their brains, as in all of ours, is locked a secret.