The sun rises on Japan.
More than 6,000 islands on the edge of the Pacific.
Life here is at the mercy
of Earth's most powerful elemental forces.
From the wilds of the frozen north...
BIRDS SQUAWK
..to the subtropical warmth of the south...
..animals along this chain of islands have had to adapt
in unique and sometimes bizarre ways.
Throughout this land, people have developed
an extraordinary relationship with the natural world...
BEAR GROWLS
..trying to capture its fleeting beauty...
..and tame its spirit.
But these islands remain wild, mysterious
and magical.
This...
is Japan.
Japan's great chain of islands stretches for 2,000 miles.
Right in the middle is its biggest island...
..Honshu.
Here is one of the largest urban areas on Earth.
But this is a wild place too.
From the volcanic mountains to the edge of the sea,
people and nature are drawn together in the most extraordinary ways.
Tokyo.
Home to over 35 million people.
It's so densely packed,
it's hard to imagine there's any room left for nature.
BIRDSONG
But as the sun rises on a spring morning,
something magical is about to happen.
In the heart of the city,
thousands of cherry trees are bursting into blossom.
For just a few fleeting days, everyone celebrates.
No other event in Honshu is more welcomed.
This natural event is so important, it makes front-page news.
Every spring, across Japan,
people follow the sakura zensen - the cherry forecast -
eager to see the blossom at its very best.
The magic is all too brief.
The petals start to fall almost as soon as they appear.
Even in this most urban place,
people still yearn for a connection with nature.
But Honshu's cities are crowded for a reason.
Three-quarters of this island is mountainous,
where fewer people can live.
Over 20 of these peaks are more than 3,000 metres high,
pushed up by violent upheavals in the Earth's crust.
This is no place for humans.
The Hida Mountains are instead home to Honshu's wildest creatures.
A black bear.
And this one's hungry.
He'll spend eight hours a day flipping rocks, looking for ants.
It might not seem much to keep a bear going.
He's not on his own up here.
A Japanese macaque is also looking for a meal.
But for these dextrous monkeys there are alternatives.
These miniature trees, pruned by the elements, are covered in pine nuts.
Full of fat and easy to reach.
But despite these rich pickings,
Honshu's macaques have learned
that there are even easier ways to make a living.
But to reach it, they have to venture off the mountain peaks...
..and that will bring them into contact with people.
No matter how wild it seems, there's nowhere in Honshu
where the paths of people and animals don't cross.
This crowd of macaques is on a mission,
all heading down the mountain to the same place.
In among the rocks, there's a pool heated by volcanic springs.
The temperature of a warm bath,
it's just the thing in the chilly mountain air.
This was once a spa for the exclusive use of humans.
Back in the '60s, one young macaque discovered the hot tub,
and liked the warmth.
News spread, and now they've claimed it as their own.
It's so popular, there can be hundreds of macaques here every day.
And thousands of adoring tourists
venture into the mountains to see them.
These are some of the most photographed animals on Earth.
But they are not just here for a bath.
They're onto a very good thing.
Each macaque has its favourite way of retrieving the treats.
You can try holding your breath
and stuffing as much into your mouth as you can.
But if you don't like getting your hair wet,
there's a daintier technique.
One for the more refined.
At the end of the day, when the tourists have gone home,
they make their way back to the mountain forest.
But this is still a wild place, full of dangers for a young macaque.
It's no place for a swimming lesson.
MACAQUE SQUEALS
There are no gentle streams here.
Water tumbles off these mountains at four tonnes a second.
The Shomyo Falls are Japan's highest.
The water cascades over 300 metres -
taller than the Eiffel Tower.
Despite falling so far, the water doesn't roar,
it murmurs.
People say it sounds like the chanting of prayers.
It may be a wild journey down the mountains
but this raging water is about to be tamed.
As it reaches the foothills,
the torrents are gradually controlled and channelled.
With so much pure water on tap,
people can grow Japan's most important crop.
These are Honshu's traditional rice paddies.
Flat land is scarce,
so these fields have been painstakingly carved out
of the foothills and water guided in.
These man-made marshlands, perched on the edge of the mountains,
are a magnet for wildlife.
At the start of summer, as soon as the rice is planted,
mysterious white globes start to appear
in the trees around the paddy fields.
The paddy fields can be a dangerous place to raise your young.
Hungry mouths are everywhere.
So some mothers have taken to the trees
to give their babies a fighting chance of survival.
FROGS CROAK
The white globes are being made by these Japanese tree frogs.
It's the breeding season
and the trees are teeming with frogs.
The female is with a male at the tip of a branch,
perched above the paddy pool.
She's building a nest by whipping up a giant ball of foam
with her back legs.
She lays hundreds of eggs inside.
She's attracting the attention of other males.
Each male could still fertilise some of the remaining eggs in the foam.
They're coming in from all directions.
But the foam makes it hard to get to grips with the competition.
Things quickly descend into an undignified wrestling match.
This male's work is done here.
It's time to move on and find other nests.
But when you're covered in slippery foam,
it's hard to leave with dignity.
It's an unusual problem for a tree frog.
As the days pass,
the eggs develop in the safety of their foam nest.
The temperature rises with the summer sun,
and the foam ball dries to form a protective case.
The tadpoles inside are still moist,
and six degrees cooler.
But the little tadpoles need rain.
At this time of year,
warm air is rising over the steep Honshu mountains
and clouds are starting to build.
The tree frogs have timed their nest-building perfectly.
After 20 days, conditions are just right
and the waiting is over.
The hard foam starts to dissolve and the tadpoles drop out,
straight into the nursery pool of the rice paddy below.
They feast on the remaining pieces of the nest -
a final meal before they take their chances in the big, wide world.
Their mother has pulled off a remarkable feat of planning.
Over a third of Japan's fresh water goes to its paddies.
Everyone relies on this precious resource
and there are some uniquely Japanese ways of keeping it pure.
The little village of Harie has a network of interconnecting canals.
But these are not just any streams,
they're part of an ancient system called kabata.
The water is piped into small buildings close to each house.
This is where Mrs Fukuda prepares her vegetables
and does her washing up.
All this waste should make the water dirty
but it's not.
It stays sparklingly clear.
That's because Mrs Fukuda
has an unusual band of kitchen helpers.
Giant carp.
As she washes her food and plates, the carp move in.
Carp are natural ground feeders,
sucking up the crumbs that sink to the bottom.
As Mrs Fukuda rinses out her rice bowls,
the carp pick out the bits of food
and clean the water at the same time.
No detergents, no waste,
just some very obliging, well-fed fish.
The same water is now piped out of the kitchen and on to the crops,
clean and clear, for the benefit of everyone on the lowlands.
They call this place 'the village of living water'.
And around the edges of these waterways, on summer nights,
something enchanting happens.
As darkness falls, the air is filled with tiny lights.
Fireflies.
They can only thrive if their watery world is pristine.
They've spent most of their brief lives as larvae,
living in river beds.
But for just a few weeks in summer,
they emerge as adults to find partners.
The female flashes her abdomen to attract attention.
Soon, she's surrounded by eager males,
all synchronising their flashes with hers.
People call this dancing swarm a firefly contest.
They've caught the imagination of countless generations.
People once thought they were the fire of human souls,
floating in the night.
The female has found her mate.
It will be a brief relationship.
In a few weeks, they'll all be gone.
But the pure water has created a magical, fleeting encounter
between people and wildlife.
There's a strong spiritual connection with nature
in these mountain heartlands.
Over half of Honshu is still thickly forested...
..and people believe the oldest trees
are inhabited by kodama -
tree-spirits.
The forests echo with their voices.
LOUD HOWLS AND SCREECHES
It's bad luck, so they say, to cut down a tree where a kodama lives.
But there's another elusive creature in these ancient forests
that was once hunted almost to extinction.
People call it the cow demon or the phantom.
It's a Japanese serow.
This relative of antelopes and goats is unique to Japan.
It's a strange, stocky creature,
but it has a certain quirky charisma.
When numbers fell dangerously low,
the Japanese government banned hunting.
The serow was saved and it's become an unlikely national icon.
But it's a hard one to get to know.
At the slightest hint of danger, it will vanish into the forest...
..like a ninja.
These are still wild woods.
But as you leave the foothills, the land flattens
and it becomes easier for people to settle.
It's when animals leave the forest edge and move into farmland
that the relationship with humans becomes less benevolent.
The macaques of the lower forests
are as bold as their mountain cousins
and often venture out in search of new opportunities.
CAR HORN HONKS
There are all sorts of perils,
but there are rewards too, if you're willing to take some risks.
CAR HORN HONKS
For over 100 years, people have been growing
the finest fruit and vegetables on these warm, rich soils.
For these cheeky thieves, it's irresistible.
Growing perfect produce is a Japanese obsession
so the last thing people want is marauding macaques.
As the day heats up, the farmers take a break.
The coast is clear.
They have to be cautious.
If they're spotted, there'll be trouble.
But every day they brave the electric fences.
They know all the weak spots where they can stage their raids.
And they gorge themselves on the fruit of the farmers' labours.
They are almost impossible to stop
but the farmers are not prepared to give in.
DOG BARKS
They bring out their secret weapon.
Specially-trained monkey dogs.
DOG GROWLS
The Japanese Shiba Inu is one of the world's oldest breeds
and people have trained them to protect their crops against monkeys.
There's even a Japanese saying that when people are fighting,
they're like a dog and a monkey.
But the rewards outweigh the risks.
They'll be back again tomorrow.
But fruit farmers aren't the only ones
having to outwit hungry visitors.
Mr Nakayama has been keeping honeybees for more than 65 years
and these sunny forest clearings are perfect for his hives.
But every year, Mr Nakayama's hives come under attack.
Whatever it is seems to be unfazed by a swarm of angry bees.
Mr Nakayama has put an electric fence around his precious hives
but even this doesn't seem to be keeping the culprit out.
So he's called in some experts
and they've set up an elaborate trap laden with honey.
All they can do now is wait.
And it doesn't take long.
Within just a few hours, news comes in that the trap's been tripped.
GROWLING
Professor Izumiyama and his team are here to help.
Although it's wise to tranquillise it first.
It's a young black bear.
He's strayed dangerously close to the edge of human habitation,
looking for something to eat.
Black bears have attacked people in the past
so, for everyone's sake, he can't stay here.
There's just enough room for the bear in the boot.
He needs to be returned to the safety of the mountain
but it's a one-hour drive.
The bear could awake at any time.
And there's no cage!
In this rural area,
bear expert Professor Izumiyama is used to taking this chance.
They need to take the bear
as deep into the mountain wilderness as possible.
This is the most anxious time for the professor.
Thanks to Professor Izumiyama, this lucky bear
is back in the safety of the forest and out of harm's way.
All across Honshu, big towns have grown up along the forest edges.
Some are more than 1,000 years old.
Here, links with nature are rooted in the most ancient beliefs.
These sika deer live in the hills around Nara,
one of the oldest towns in Japan.
But, every morning, they leave the safety of the forest
and head straight into town.
Their destination is one of the most sacred places in Japan.
The temple is the world's largest wooden building.
Large enough to house a 15-metre statue of Buddha.
It's visited by thousands of pilgrims.
The deer are allowed in
because they're believed to be messengers of the gods.
No-one is allowed to harm them.
Legend has it that a god arrived at the shrine of Nara
riding on the back of a deer.
1,200 years later, the deer are still regarded as sacred.
They've become local celebrities.
And they take full advantage of the situation.
150 yen buys you a bag of deer biscuits.
For many people visiting the temple,
this may be as close to wildlife as they will ever get.
But the relationship clearly needs some finessing.
Some of the deer take unfair advantage of their sacred status.
LAUGHTER
As with all things in Japan,
courtesy and respect goes a long way.
A simple bow is quickly rewarded and everyone is happy.
When they've had enough biscuits,
the Nara deer head back to their home in the forest.
But as you travel further from these mountain fringes,
the landscape of Honshu is swallowed up in an urban sprawl.
Every inch of the remaining flat land to the coast
has been taken over by people.
Over 35 million people are crammed into an area smaller than Yorkshire.
In this concrete landscape,
it would seem unlikely that any wildlife could survive.
But one animal has made the city its home
and it has a strangely charmed reputation.
People even put fat little statues of it outside bars and restaurants.
It's naughty, but it's also believed to bring good luck.
Tanuki - the raccoon dog.
It's a creature of the forest
but, as buildings have replaced trees, it's been forced to adapt.
These little creatures will eat almost anything.
There's an opportunity at every turn.
Tanuki make mischievous neighbours.
But people think they're lucky, so they get away with it.
They're so comfortable with urban life, they never leave.
TANUKI CUBS SQUEAL AND CHITTER
This mum is raising her brood next to a busy railway line,
which could be lethal for cubs newly out of the den,
but they grow up fast and quickly become streetwise.
TRAIN BLASTS HORN
Maybe they deserve that lucky reputation.
All across this crowded island,
people and nature are thrown closer together.
In Japan's ancient Buddhist and Shinto philosophy,
harmony with nature is an essential part of life.
Mr Watanabe is hard at work.
The space he is tending is called karesansui -
dry mountain and water.
Mr Watanabe has transformed Honshu's great mountains
and raging torrents into something beautifully simple.
It's nature in its purest essence,
for people to observe and reflect on.
But this is a land where the forces of nature are impossible to tame.
WATER GUSHES LOUDLY
Honshu sits at the mercy of four slabs of the earth's crust.
Every year, there are nearly 5,000 earthquakes and tremors.
The rocks steam and hiss with sulphurous gases.
It's no wonder the Japanese call these areas Jigokudani -
Hell Valley.
No-one is far from an active volcano.
Mount Fuji is just 60 miles from Tokyo.
This volatile landscape continues all the way to the coast.
These cliffs at Sanriku were pushed 200 metres above the sea
by violent upheavals under the ocean floor.
WAVES CRASH LOUDLY
This eastern coastline is regularly battered by tsunamis.
On the west coast of Honshu,
geological forces have formed a vast trench that runs just offshore.
But here, this extreme landscape creates a rare moment of magic.
An underwater valley, nearly 2,000 metres deep, runs close to shore.
The local fishermen are so in tune with nature,
they know exactly when conditions are right
to cast their nets above the deep valley.
ENGINES WHIR
GULLS SQUAWK
Something is stirring far below the boats.
These are firefly squid.
They spend most of their lives 300 metres down in the ocean depths,
signalling to each other in the darkness
using bioluminescent chemicals in their skin.
But on spring nights, the currents carry them up to the shallows,
where they mate and spawn.
As the eggs float back to the depths,
the squid's lifecycle comes to its natural end.
The fishermen have waited months for this brief event.
The squid are barely eight centimetres long
but there are millions of them.
It's a valuable catch of sushi.
GULLS SQUAWK WILDLY
As the fishermen haul in their nets, they may see something even rarer.
For just a few nights of the year,
if the moon, the tide and the wind are aligned,
the dying firefly squid are swept ashore.
It's the last, dazzling moment of their lives.
Between the turbulent sea and the inhospitable mountains,
there may be little room left to live,
but nature is still appreciated by millions of people.
Late at night in Tokyo,
the cherry blossom celebrations are ending with a great party.
Hanami, or blossom-viewing parties,
have been held here for more than 1,000 years.
People gather under the trees to eat traditional food,
helped along with some sake.
But there's a poignancy to all this revelry.
Cherry blossom only appears for a brief moment in spring.
Within just a few days, it will all have fallen.
The delicacy of the flowers captures a particularly Japanese sentiment...
..the spirit of "mono no aware".
It's a wistful understanding of the transience of life.
All this will come to an end and it must be appreciated in the moment.
It perfectly captures the Japanese connection
to the natural world.
In such a crowded island,
people and nature must find ways to live together.
But all across Honshu,
there's an ancient bond with the natural world
that still runs deep.
There aren't many places in the world where the lives of people
and animals cross so closely as on Honshu.
Here, there are two animals that can cause havoc.
Japanese macaques and black bears.
This is a front line,
where these two animals are always in conflict with people,
so that makes it a challenging story to tell.
OK and go ahead.
Cameraman John Brown has filmed these interactions before
and knows how tricky they are.
OK, I think probably this end, I would say.
SHE SPEAKS IN JAPANESE
But the team are working with some extraordinary and passionate people.
OK. I think we should...
Professor Shigeyuki Izumiyama is a bear biologist
and he knows this area very well.
He's spent the last 25 years rescuing and relocating black bears
that have strayed too close to human habitation.
Professor Izumiyama is an incredible individual.
He's a brilliant biologist that really understands his animals.
He's the only individual, as far as I know,
who's trying to tackle this problem.
The film crew are keen to film him catching a bear.
As soon as the next trap is sprung, he'll give them a call.
Meanwhile, the team are trying to film the other problem animal -
the macaques that raid the farmlands.
Filming macaques crop-raiding is a huge challenge
because they see any human presence as a major threat,
so they'll run as soon as they sense that they have been noticed.
So I guess the important thing is to kind of get a sense
of which direction they're going, if they're coming down...
They are being helped by scientist Takayo Soma.
She grew up round here, so she knows the situation very well.
Finding macaques is easy,
but the team want to film their crop-raiding behaviour.
That's not so straightforward.
EXPLOSION
The farmers are keen to move the macaques on
and they use firecrackers and dogs to scare them away.
DOG BARKS
The macaques cause £5 million worth of damage every year,
so it's understandable.
It's such a big issue, there's even a monkey policeman on patrol.
I think he's following us now.
I think he knows we're onto something.
The crew just need a bit of time to film,
so Takayo goes to negotiate.
She has a trick up her sleeve.
SHE LAUGHS
You bribed him with an Oreo? You gave him some biscuits?
He gave you a biscuit? I had biscuit.
That's genius. How many bites? He just took one bite.
Two bites. Two bites?!
That's a brilliant bit of work. Wow, he's got a pretty low price.
But just as the coast is clear,
director Gavin Maxwell gets a call from Professor Izumiyama.
The previous night, up in the forest,
a bear wandered into one of the traps.
The bear was caught last night
and we're going as fast as we can to get to this site now.
It's about 45 minutes away.
So we're in a bit of a race to get there in time.
LOUD CLATTERING
Big bear in there.
As well as relocating bears,
Professor Izumiyama also studies them.
By fitting radio collars to track them,
he hopes to discover more about their movements.
I'm not sure how much more time we've got.
They have to work fast, before the drugs wear off.
(Does the bear have a name?)
Hirokun. Hirokun.
As Hirokun begins to stir, it's wise to take some precautions.
Just John and Izumiyama-san we'll leave here.
So we should retreat to the inside of the car? Yeah.
Professor Izumiyama carries pepper spray
just in case of attack.
John knows how nervous local people can get.
People get so scared and so angry about these bears
that unless he did something, they'd just end up dead.
A few hours of unpleasantness, which it will have forgotten by tomorrow,
is well worth it.
Another bear on its way, but now its movements can be tracked.
Hunter. Yeah, that one. If, maybe in a weeks' time...
Over 25 years, Professor Izumiyama has caught a lot of bears.
More than 1,000. More than 1,000 bears.
THEY LAUGH
1,000 bears and counting and there's no sign of stopping yet.
As soon as one bear is released, it's straight on to another.
Throughout the summer, he's on call 24/7.
Despite being such a populated country,
Honshu is home to over 10,000 bears...
TRACKER PINGS
..and what Professor Izumiyama is discovering is remarkable.
These bears have huge territories.
They can roam nearly 50 square miles in search of food.
All this effort will help to keep bears away from people
so that both stay safe.
The next day, the team are back on the plains,
still trying to catch the macaques staging a crop-raid.
We haven't seen anything.
Anything interesting? No.
But with Takayo's expert help,
they are learning to predict the macaques' movements.
You might spot a macaque or two who are, kind of, looking a bit shifty
and you kind of get the sense that something's going to happen.
And then, at last,
they are in the right place at the right time for a raid.
Is that an apple in his hand?
Caught red-handed.
In a place with such close proximity between people and animals,
the relationship is always going to be challenging.
But Professor Izumiyama has seen a big change in attitudes
since he first started working with bears.
Next time, we head to Japan's far south.
This is a land ruled by the power of the sea.
Here, you have to make the most of every opportunity.
And the further south you travel, the stranger life becomes.