Japan is one of the world's most

populous countries. Home to around 123

million people today, Japan is the

world's 11th most populous country and

it's also home to the world's second

most populous island, Honshu. Home to

more than 83% of the Japanese population

and more than 102 million people all on

its own. But when you look just beneath

the surface of these statistics, you'll

see that Japan is one of the most

unusual and interesting population

patterns in the world. Because the vast

majority of Japan's population all just

live within a relatively small and

linear line that runs across the center

and east of the country's south. Nearly

twothirds of the entire Japanese

population all just live within this

line that encompasses most of Japan's

largest metropolitan areas including

Fukuoka, Hidiushu, Hiroshima, Okyama,

Takamatsu, Kobe, Osaka, Kyoto, Nagoya,

Hamamatsu, Shizuoka, and of course the

biggest of all, Tokyo. Roughly 80

million Japanese live within this long

but narrow line that extends for around

1,200 km across an area that only makes

up less than 10% of Japan's total land

area leaving behind the remaining 90% of

the country that's significantly more

sparsely populated. To help you

visualize this divide better, roughly 80

million Japanese live within the line

that makes up less than 10% of the

country's area, while only about 43

million Japanese live within the rest of

the 90% plus of the country. Nearly half

of the population lives within the much

much smaller line. The line of Japan

contains an average population density

that's nearly 17 times greater than the

rest of the country has, which is one of

the most astonishing differences between

two different regions of the same

country seen anywhere in the world. Put

another way, the lion of Japan all

throughout is even more dense than the

crowded citystate of Vatican City is.

While the rest of Japan has an average

population density that's about the same

as the US state of Pennsylvania.

Economically, the line also accounts for

an even more astonishing 70% of the

entire Japanese economy. This highly

populated and economically powerful line

across Japan has been referred to by

many different names. Sometimes it's

referred to as the Thai belt, which in

English means Pacific belt, and other

times as the Tokaido corridor. I will

continue referring to it from here on as

the Taiheo Belt. And in many ways, it is

fairly comparable in both size and scope

to the northeast megalopouloolis in the

United States. The most densely

populated continuous urban area in North

America that runs across the cities of

Washington DC, Baltimore, Philadelphia,

New York City, and Boston.

Geographically, the Taio Belt is a bit

larger. placed side by side with Fukuoka

beginning where Washington DC begins,

the Taiheo Belt would extend across the

entire northeast coast well beyond

Boston with Tokyo placed roughly in

central Maine with around 80 million

people living across it. The Thai belt

is also significantly more populated

than the Northeast Megalopouloolis is as

well, which is home to only about 53

million people by comparison. This

difference in population density and

scale between the two partly explains

the dramatically superior rail

connectivity across the Taio belt that

exists today. Japan's famous Shingansen

bullet train network connects the entire

corridor together today and enables

rapid transport from Tokyo to Fukuyama

at only about 3 and 1/2 hours. Roughly

half the time that it takes Amtrak

Asella to cover the same distance from

Boston to Washington DC at about 6 hours

and 40 minutes. But all of this begs a

fundamental question. Why does Japan's

human geography look like this in the

first place? Why does so much of Japan's

population all live crammed together

within a relatively narrow straight line

across a small part of the country? And

why is the rest of the country so much

more relatively empty by comparison?

First of all, it helps a lot to just

simply look at a topographic map that

shows Japan's elevation. Japan is one of

the most mountainous countries in the

world with about 73% of the country's

total land area covered by them, leaving

behind only about a quarter of the

country left for significant human

habitation in the few scattered areas of

flatter land where urban development is

easier and more affordable. Since time

immemorial, this fact has left the

people of the Japanese archipelago

restricted to living within close

proximity to each other along the

coastal plains and across the few

flatter areas within the interior where

some stepped rice fields can be placed

in the hills. There are pockets of flat

land found all across the country from

the west to the east and from the north

to the south. But you will note how the

Thai belt follows across what happens to

be the three largest continuous areas of

flat land found anywhere in the country.

The Kai plane that encompasses the

cities of Osaka, Kobe, and Kyoto. The

Noi plane that encompasses Nagoya. And

the single largest plane of all that can

be found anywhere in Japan. The Kanto

plane that encompasses the mega city of

Tokyo. All three of these planes also

have large rivers that flow through them

that make them ideal centers for

agriculture and supporting large

populations. The Nagoya metropolitan

area, crowded within the Novi plane, is

Japan's third largest metro area, home

to more than 9.3 million people. The

Osaka metropolitan area crowded within

the flat kai plane is the second largest

home to more than 19.3 million people.

While the Tokyo metropolitan area

crowded within the Kanto plane is the

largest not only in Japan but in the

entire world with more than 41 million

people living there today. More than

double the population of the New York

City metropolitan area in the United

States. Collectively, these three planes

alone are home to nearly 70 million

people. Most of the population lives

within the whole Taio belt and indeed

more than half of the entire nationwide

population. They've historically been

the most major population, economic and

political centers in Japan for centuries

now that have long dominated over the

rest of the country. But that's not just

because they're the three largest areas

of continuous flat land available for

cityb building. The western side of the

island of Hanju that faces the Sea of

Japan has some areas of flat land around

the coast, too. But on top of none of

these areas being quite as large as the

Kenai, Novi, and Kanto plains that are

over on the Pacific side, they have

multiple other disadvantages that have

always made them less attractive places

to settle in as well. For one thing, the

Pacific side of Japan, for whatever

reason, was also blessed by the RNG

geography gods with significantly

larger, deeper, and more useful natural

harbors as well. Almost miraculously,

Japan is home to not one but two of the

most incredible natural harbors that can

be found anywhere on the planet that are

simultaneously huge, deep, exceptionally

wellsheltered and directly connected to

large flat hinderlands that can support

huge adjacent population centers, Tokyo

Bay and Osaka Bay, which of course are

also directly connected to the huge flat

Kanto and Kenai plains. Tokyo Bay in

particular, large, very deep, very well

sheltered, and surrounded by the flat

Kanto plane that's home to Tokyo and

it's 41 million people, is so comically

overpowered from a commercial trade

perspective that it alone handles around

350 million tons of seaborn cargo

annually, which is comparable to the

entire maritime trade volume of the

whole of Italy combined. While not quite

as exceptional as the Tokyo and Osaka

bays are, the Eay Bay that connects

directly to the Nobi plane where Nagoya

is concentrated is also still world

class, being huge, deep, and fairly well

sheltered with the huge Nobi plane

directly adjacent. Obviously, these

three worldclass natural harbors that

just so happen to directly connect to

the three largest flat planes in the

country made them even more obvious

centers to settle in in order to

capitalize on the ridiculous commercial

trade and naval potentials. But on top

of these three, the Pacific side of

Japan has many other excellent natural

harbors as well, including the

Kangoshima and Nagasaki bays on the

Pacific facing side of Kiushu and

Hiroshima Bay on Honu. The western sea

of Japan- facing side of Honshu by

comparison is nowhere near as jagged as

the Pacific facing side is. It is

significantly smoother and as a result

it has nowhere near as useful of natural

harbors and ports as the Pacific facing

side has. The only notable harbors on

the Sea of Japan side of Honshu are

Misuru Bay and the Porta Nigatada, but

both of them are still just a tiny

fraction of the size of the massive

natural harbors over on the Pacific side

like the Tokyo and Osaka bays. And

neither of them are connected to as

large of a flat plane in the interior

that can support millions of people

nearby to sustain trade. The Sea of

Japan side of Honshu and the entire

northern island of Hokkaido simply have

nowhere near as ideal natural harbors to

utilize for trade and commerce, on top

of nowhere near as large of planes to

build cities in, compounding other

disadvantages to support huge

populations even further. And to make

the Pacific side of Japan even more

advantageous, it also has the Sato

inland Sea, which is without a

coincidence placed directly in the

center of the Taiheo Belt. Because the

vast majority of Japan's land mass is

mountainous, the islands have an

abundance of water. But the dir of flat

land also means that nearly all of the

rivers running through the interior are

rough and full of rapids and waterfalls

that make them completely unsuitable for

interior navigation and trade. Something

that's made even worse by the fact that

most of the rivers don't even connect

together either. But what Japan does

have that more than makes up for the

lack of navigable rivers is the Sato

Inland Sea. the largely enclosed body of

water that's protected from the rest of

the Pacific between the main islands of

Honshu, Hyushu, and Shikoku. Between

these main islands, there are only four

very narrow straits that connect the

Sato Windland Sea with the rest of the

greater Pacific, which makes its water

significantly more calm than anywhere in

the surrounding ocean. While the tidal

currents within the four narrow straits

leading into and out of the sea can be

strong and complex, the rest of the sea

is exceptionally navigable and it

blesses Japan's geography with one of

the largest internal seas for navigation

and trade that can be found anywhere in

the world. To give you just a sense of

the Sato Woodland Sea's scale, if you

placed it over the northeast coast of

the United States, it would stretch from

Washington DC beyond New York City into

a southern Connecticut. There's also

around 700 separate smaller islands that

can be found dotted all across the Sato

Woodland Sea as well. Several of them

complete with their own incredible deep

natural harbors that provided abundant

safe anchorage and stopovers for ship

steering storms [music]

which made the whole body of water

perfect for early maritime trade during

the ancient and medieval eras. [music]

The sea also provides a moderating

effect on the regional climate around it

to the extent that it's often referred

to as Japan's Mediterranean, an area

with year round warm temperatures that

supports yearround navigation and

agriculture. During pre-industrial times

in Japan, building roads across Japan's

mountainous terrain to connect disperate

flat areas together was extremely

difficult. But the calm waters of the

Sato Windland Sea provided a critical

alternative for much easier and

efficient sea-based transportation

instead. Even better at the eastern edge

of the sea, the presence of a waji

island created the even further enclosed

Osaka Bay within it, directly connected

to the huge flat area of the Kenai plane

in the interior. Thus, from early on

within Japan's history, the Sato

Windland Sea became the critical

maritime trade artery that connected the

Kenai plane in the Osaka Bay and all the

other areas around its shorelines with

the rest of Honshu to the east,

including the Nobi and Kanto plains with

their own ideal harbors. And with

mainland Asia and Korea further to the

west, all of this huge trade volume

flowing through it transformed the Sato

Windland Sea into the wealthiest area of

Japan for centuries, which encouraged

settlement around it and which in

particular directly contributed to the

massive population growth in the Kenai

plane that gave rise to Japan's early

political center in Kyoto and what

eventually became the mega port city of

Osaka. For centuries, it was Osaka that

was the economic epicenter of Japan

because of all of these advantages. And

by the time of the Tokugawa shogunit,

all of Japan's feudal lords, known as

Damio, had established an office in the

city that were known as Osakaya Shiki,

which were among the earliest forms of

banks in Japan, which further reinforced

Osaka's early importance. And by the

time of the industrial age, the other

cities around the sedland sea like Kobe,

Okyama, Takamatsu, Fukuyama, Hiroshima,

and Kea Kiushu all developed into major

industrial shipping and naval centers as

well, carrying over the Sato Windland

Se's importance into the modern era and

further solidifying the population

concentration within what would become

known as the Taihillo belt that runs

directly across it. After the Tokugawa

shogun had managed to largely unify

Japan in the early 17th century, the

shogun decided to establish the seed of

their power away from the historical

imperial capital at Kyoto towards the

east at Ido within the larger Kanto

plane. One of the most profound impacts

on Japan's human geography and

population pattern that has ever

happened. The shoguns relocated their

administrative center to Ido, which

would later be renamed to Tokyo during

the 19th century in order to distance

themselves from the emperor in Japan's

traditional nobility in Kyoto so that

they wouldn't be overshadowed by them.

While they also saw the potential for

rapid urban development in the large and

expansive Kanto plane that was still

fairly underdeveloped by the time of the

early 17th century. At that time, Ido

was nothing but a small castle town that

was probably only home to a few tens of

thousands of people. But within only a

century of Tokugawa showing of rule with

Ido as their de facto capital by around

1700, its population had exploded to

more than a million people, which

transformed it from a small town into

one of the largest cities in the world

within only a couple of lifetimes.

Fueling this enormous growth of people

in Ido and the Kanto plane and elsewhere

along the modern Taihio belt during the

Tokugawa era was the shogunits centuries

long policy that was known as Sanin Ko

Thai which required all of Japan's

feudal lords or doio to alternate living

between their domain and Ido every other

year. The hundreds of damio at any given

time in Japan were forced by this policy

to maintain a lavish residence both at

their homes and in the shogun's capital

at Ido. And every other year when the

domino moved back and forth between

them, they were forced to undergo

expensive and lavish processions with

their full entouragees. For the Shogun,

the policy was a deliberate strategy to

force the domios and their families into

a state of surveillance in the capital.

[music] While the extreme financial

burden of maintaining lavish mansions in

both locations and moving back and forth

between them every other year was both

time and money that they couldn't spend

on plotting to overthrow the shogun.

Their frequent travel back and forth

with their full launchages also

incentivized road building and the

development of inns and other facilities

along the routes they took which helped

generate early economic activity along

them. Over time, five primary routes

were developed that the domios took

between their domains in Ido. And the

most used route out of all of them falls

directly along the Taihi belt today

between Ido and the old imperial capital

at Kyoto. Which meant that this route

became rapidly economically developed

across the Tokugawa era into the 19th

century and was already the most

developed part of the country leading

into the era of industrialization that

accelerated its growth even further.

Another major key to the puzzle that

influences the location of Japan's

population across the Taihill belt today

are the presence of ocean currents which

dramatically influence Japan's regional

climates. This is a map of the average

winter sea surface temperatures that are

found in the western Pacific using

satellite data. From the south, the

Kiroio current functions in a similar

manner to the Gulf Stream in the North

Atlantic, carrying warm waters from the

Philippines northward along the eastern

shores of Japan. This current brings

warm and moist air along with it, which

highly contributes to the mild winters

and humid summers that are experienced

in Kyushu, Shikoku, and southeastern

Honshu, basically immediately along the

Taihi belt. And it's what keeps Tokyo in

particular relatively warm for a city at

its latitude. At the same time, an

opposite oceanic current also comes down

to Japan from the north that's known as

the Oashio current. A cold subarctic

current that flows south from the Arctic

Ocean through the Bearing Straight that

carries frigid but nutrientrich Arctic

waters along with it. Almost immediately

northeast of Tokyo Bay, the cold Oshhio

current collides with the warm Kiroio

current, creating one of, if not the

richest fishery areas on the planet that

has always been easy to capture and

exploit from the relative safety of

nearby Tokyo Bay to help support the

population across the Kanto plane. The

cold air above the Oshio current

contributes substantially to the colder

climate that can be found in the

northern island of Hokkaido and along

the western coast of Honshu that faces

the Sea of Japan. But there's a lot of

other complex climatic effects going on

here that makes them even worse. A

branch of the warm Kiroio current known

as the Tsushima current breaks off and

flows into the Sea of Japan from the

south. But during the winters, when cold

and dry air originating from Siberia

will blow across the Sea of Japan, the

cold air masses will pick up the

moisture and warmth from the relatively

mild Tsushima current and become

saturated. When that saturated air then

hits the mountains in western Honshu and

Hokkaido, it'll rapidly cool and then

dump an absolutely enormous amount of

snow in the process. like to the point

that northwestern Honchu and Hokkaido

are among the snowiest locations that

can be found anywhere on the planet. It

also means that eastern Honshu that

faces the warmer waters of the Pacific

along with Shikoku and Kiushu experience

dramatically less snowfall than the

western side of Honshu and Hokkaido

suffer throughout the winter. An area of

Japan that's literally referred to by

the Japanese as the snow country. From a

North American perspective, the climate

found in Hokkaido is more similar to the

area around Lake Ontario, like Toronto,

Buffalo, and Rochester. The northern and

western sides of Honshu are generally

more comparable to coastal New England

and the Mid-Atlantic. While the eastern

side of Honshu, along with Shikoku and

Kiushu, are much warmer and rainier and

are more comparable to Georgia and South

Carolina. Northwestern Honshu is so

snowy because of this effect during the

winter that Ali city in the north of the

island holds the distinction of being

the snowiest major city in the world.

It's 265,000

people experience a whopping average of

8 m or 26 ft of snowfall every winter.

Nearly 6 times as much snowfall as

Minneapolis experiences on average in

the United States. Snowfall gets so deep

in some parts of the snow country that

some buildings are designed and built

with a special entrance through their

second story. All kinds of special

infrastructure considerations have to be

made in the snow country. Residents have

to remove the piles of snow that

accumulate on their roofs in order to

prevent its weight from crushing and

caving them in. Streets are often lined

with covered sidewalks to make sure that

residents can still get around in the

winter. Streets are equipped with

sprinklers that deploy warmer

groundwater to keep them passible by

melting snow. And in some towns, people

even used to tunnel paths through the

snow in order to get to each other's

homes. All of this means the development

in the snow country is just more

expensive and timeconuming than it is

elsewhere in Japan. And thus, when you

put this all together, it's pretty easy

to see why the area that became the

Taiho Belt is by far the most densely

populated part of the country and why it

has been for a very long time now. The

Taiho Belt has the advantages of the

Sato inland Sea for a large, calm, and

easily navigable body of water to

facilitate trade, movement, and

commerce. It encompasses by far the best

natural harbors that can be found in the

islands and some of the best anywhere in

the entire world like Tokyo and Osaka

bays. Both of which are directly

connected to large flat hindrlands in

the Kenai and Kanto plains with another

worldclass harbor at Eay Bay in between

them connected to another large flat

hinderland in the Noi plane which

enabled a sort of leaprogging ability

for ships early in history to take

between them in the Sato Windland Sea

that established early modern Japan's

commercial superighway. It has by far

the more milder climate in Japan

compared to the western sea of Japan

side of Honshu that gets buried by snow

during the winter. And it's also closest

to what's arguably the richest fishery

in the world off the coast of eastern

Honshu where the warm Kiroio and

coldosio currents clash together. One of

the very few notable cons of the Taihi

belt in the Pacific side of Japan from a

geographic perspective is that it's also

located across the most natural

disasterprone area of Japan as well

which experiences more damaging

earthquakes and tsunamis than anywhere

else in the country does due to the

locations of the Japanese archipelago

subsurface fault lines and the

coastline's exposure to the vast open

Pacific on this side. But these natural

disasters are sporadic enough that the

numerous advantages of concentrating

within the Taiho belt have repeatedly

outweighed them enough across the

centuries to be decisive. And that in a

nutshell is why Japan's population

exists where it does today. Now, there's

a lot of data that goes into producing

these kinds of videos. Whether it's

visually showing you the scale of the

Taihei belt compared to the US northeast

coast, detailing out how the system of

ocean currents, mountains, and wind

patterns contribute to northwestern

Japan's enormous snowfall levels, or

showing you the risk of natural

disasters across Japan that are heavily

concentrated within the Tahoe belt. The

ability to actually visualize raw data

like this on the map instead of just

reading about it in text format is

exactly what makes learning about these

kinds of geography based subjects so

fascinating to me. And it's why the

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