Encoded by R. Boisselle
On the 4th of this month, registered with Unesco’s Intangible Cultural Heritage
Japanese Cuisine
Flavor extracted from ingredients to it's maximum potential,
Japanese Traditional Food Culture
A major backbone of Japanese Cuisine is the unique sharpness of the Japanese kitchen knife.
Now, chefs around the world are drawn to the Japanese kitchen knife.
Made with generations of tradition, giving birth to the pinnacle of sharpness, by the technique of a skilled craftsman.
800℃, On the dot.
Heated steel, with a skillful eye monitoring the heat in increments of ５℃
Utilizing of the skill of Japanese sword making,  This is the essence of the remarkable Japanese kitchen knife.
Tonight, let’s take a look at the secret and skillful art of the Japanese knife that has captured the attention of the world.
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Tales of the Miracles of the World.
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Through extracting the most subtle flavors from various ingredients, culinary is dependent on the sharpness of the blade.
For example, with sashimi, the much fussed over "Pride of the edge" is the seal of excellent sharpness.
"Pride of the edge" is the single message to the customer.
With our ability to slice, we can stand relative to the customer.
From the Edo period of Japan, the traditional treasured knife, the Japanese Kitchen knife.
Amongst them, there is a knife with superior sharpness, inheriting properties from the Japanese sword.
That knife is, the Honyaki Knife.
And just how sharp is this knife?  Let’s test this with the common, hard to slice Tomato.
Placing it on a cutting board, and cutting from the side.
It slices easily and thinly.
This is the remarkable and unique sharpness of the Honyaki Knife.
Let’s analyze the cross section of a slice of sashimi under the microscope, sliced by the Honyaki Knife.
Here, the unevenness of the cross section is categorized by colour.
Almost completely green, we can see that it’s completely smooth.  
Additionally, turning it to its side, we can see the shape of the slice.
This sharpness has a tremendous influence on flavor.
A knife with this amount of remarkable sharpness, you can slice with one stroke,
therefore leaving surrounding cells undamaged, allowing you produce a delicious slice of sashimi.
Mr. Takano has tested 50 over knives.
At the end of his search, he finally found the remarkable Honyaki knife.
With the Honyaki knife, it has a sharpness able to cut in a perfect straight line.
The Honyaki Knife has become a standard tool for high-end chefs around the globe.
But how was a knife this sharp invented?
To find this secret, we turn to the ancient traditions of Japan.
Osaka, Sakai City.
In a town with 600 years of sword craftsmanship history, we find a blacksmith of the Honyaki Knife.
Meet Blacksmith Ikea Tatsuo, who has been practicing his craft for 58 years.
He shares with us the history of the ultimate sharpness in a knife.
Ofcourse, sharpness was the first thing thought about.
He shares with us the history of the ultimate sharpness in a knife.
Ofcourse, sharpness was the first thing thought about.
After that, you think about things like how it would cut, how it should cut, and so on.
 I couldn’t cook, but I could see everything about how the blade would cut.  If I didn’t understand the way it would be used, I wouldn’t know how to make it. 
After that, you think about things like how it would cut, how it should cut, and so on.
 I couldn’t cook, but I could see everything about how the blade would cut.  If I didn’t understand the way it would be used, I wouldn’t know how to make it. 
The Honyaki Japanese knife is made from one piece of hammered steel.
The manufacturing process is split into three major parts.
First, the piece of Japanese steel is heated, hammered, and forged into the shape of a blade.
Next, a soil coating is applied onto the steel.
Finally, the coated sword is heated, then quickly cooled, hardening the steel.
But how was the ultimate in sharpness created?  For this answer, we turn to the secrets of blade-making.
Forging - The battle against time
We begin with the forging process.  This is where the general shape of the knife is created.
This steel is made from iron, containing 0.2 - 1.7% carbon.
Harder than average iron, both the carbon and iron become fragile.
The creation of the blade is heavily dependent on the control of this carbon.
The steel is heated, where it becomes soft.
The electronic hammer strikes the steel at 150 - 200 strikes per minute.  This is where the steel is forced into the shape of a blade.
Steel cools quickly.  From here, it’s a battle against time.
If you look closely, you can notice black spots within the red steel.
This is the biggest reason for speed.
 These black spots are oxides, spots of rust. When the temperature rises, these spots appear quite fast.
When iron is exposed to the air, it combines with oxygen and starts to oxidize.  In short, it starts to rust.
If this happens, the mix with oxygen speeds up, and so does the rate it rusts.
With skill and speed, a skilled blacksmith finishes this process in 10 minutes.
This is the result of 10 years of training for the average blacksmith.
With skill and speed, a skilled blacksmith finishes this process in 10 minutes.
This is the result of 10 years of training for the average blacksmith.
Soil Coating - The birth of the well balanced blade
The knife is hard, and cuts well.
However, a knife can’t simply be only hard to cut well.
Looking at the blade, it’s unmistakably hard.
However its hardness goes hand in hand with becoming brittle.
Looking at the blade, it’s unmistakably hard.
However its hardness goes hand in hand with becoming brittle.
Other than the cutting edge of the blade, there is an area that remains soft in order to counteract this.
In order to maintain the ultimate in sharpness, it must stay firm, but also be able to absorb impact through softness.
For example, cutting through a fish, if a knife was simply only sharp, the blade would be destroyed.
Additionally, cracks in the blade would widen, causing the knife to break.
Other than the edge of the blade, softness is equally important.
In each knife, softness and hardness are perfectly balanced.
But just how is this done?
In a typical knife, this is done by affixing an extra area onto the knife.
A soft piece of iron is folded, and fixed and forged into the hard area, creating a blend of hardness and softness.
However, in the case of these hybrid knives, if used for an extended period of time, the blended areas can begin to warp, and eventually bend.
In the case of the Honyaki knife, how does this knife maintain a blend of hardness and softness?
he key is in the ripple of the knife.  The pattern of the ripple wave acts as boundary of this balance between these two textures.
A knife can only be made by a human.
Therefore the Honyaki knife can only be made in a place like Sakai City.
The ripple of the Honyaki kitchen knife.  Identical to the ripple of the Japanese sword.
Mr. Ikea is at the factory.  This is where the skill of creating the Honyaki knife was born.
But just how is the hardness and softness in each knife created?
We will get this answer from the skilled craftsman himself!
Made from pure steel, this is the Honyaki Knife.
What is the secret to achieving the ultimate balance between hardness in softness in one quality knife?
This secret is, the soil coating.
Made from clay and grindstone, the coating is applied over the steel.
The mixture is actually not clear, and has been a secret amongst craftsmen.
This secret coating is then heated, and applied.
Keeping a soft texture, from the inside out.
To keep the cutting edge hard, the coating is thinly applied with a brush.
Through this coating process, this is how the knife is able to keep its unique balance.
Tempering - The remarkable sharpness
Through this coating process, this is how the knife is able to keep its unique balance.
Tempering - The remarkable sharpness
The final process to achieving this balance is, the tempering process.
The steel is heated, and then immediately cooled, which then becomes hard.
The final process to achieving this balance is, the tempering process.
The steel is heated, and then immediately cooled, which then becomes hard.
On the other hand, if the steel is gently cooled, it becomes soft.
Tempering is the process of heating the steel, then quickly cooling it by submerging it in water to become hard.
In that case, why does it become hard when quickly cooled?
Through this way, carbon particles melt correctly into the steel.
If steel is heated to over 727℃, iron attracts carbon particles.
Through this way, carbon particles melt correctly into the steel.
If steel is heated to over 727℃, iron attracts carbon particles.
At this state, this is what happens when you cool the heated steel.
Instantly the particles inside the cooled steel become trapped, and are forced to become solid.
In this way, the steel becomes instantly hard.
Instantly the particles inside the cooled steel become trapped, and are forced to become solid.
In this way, the steel becomes instantly hard.
This time is also important for any excess materials from the steel.
The cooling process of the area with the thicker coating is slowed down, while the area with the thinner coating is quite fast.
 This is what forms the hard area of the blade.
The cooling process of the area with the thicker coating is slowed down, while the area with the thinner coating is quite fast.
 This is what forms the hard area of the blade.
Next, the knife is lightly sharpened.
The splendid ripple.  This is the boundary between hardness and softness.
Mr. Ikea controls the cooling speed by the thickness of the coating.  Through this, he controls the Knife’s hardness.
We carried a tempered piece of steel to a laboratory for analysis.  What was discovered was….
The entire knife is quite firm from the blade to the tip.  Also the blade itself is twice as hard than the point.
This is the result of using a soil coating, and tempering.  The skilled craftsman’s sklll of balancing hardness and softness into one knife.
Technique and Skill - Reading temperature with the human eye
This is the remarkable cutting power of the Honyaki Knife.
This is the craftsman of this remarkable knife.
What is the most important step?  We asked Mr. Ikeda.
Definitely temperature management.
Without a doubt.
Normally, the Honyaki knife is heated at between 750℃ 850℃, then tempered.
Without a doubt.
Normally, the Honyaki knife is heated at between 750℃ 850℃, then tempered.
Carbon is able to enter the knife easily.  At this range of temperature, the steel won't be at any risk of damage.
But what if the steel was tempered at a different temperature?  We were shown what would happen at 900℃.
Only a 50 difference, the steel bends.
However, how would they judge the temperature at a time without modern heat gauges?
The answer is, with a blacksmith's eye.
This is a chart showing the colour of heated steel, in increments of 50.
It is possible to tell the difference by shades of red in the steel at 50℃.
However, in the case of Mr. Ikeda…..
I can tell the difference in increments of 5.
Just how does a blacksmith read the temperature in increments of 5?  This remarkable skill is ideal for tempering.
800℃ on the dot.
After years of practice, the skilled master has finally gained the ability to pinpoint the perfect temperature of 800℃.
When the outside surface has been heated to 800, the inside reaches to just about 750, prime for tempering, and hardening the steel.
However, anything hotter ruins the steel.
The control of the temperature is ultimately done by Mr. Ikea’s eyes.
However, anything hotter ruins the steel.
The control of the temperature is ultimately done by Mr. Ikea’s eyes.
With that, through the help of a heat monitoring device, we were able to see this skill for ourselves.
After inserting the steel into the fire, the wait is about 2 minutes.
With that, through the help of a heat monitoring device, we were able to see this skill for ourselves.
After inserting the steel into the fire, the wait is about 2 minutes.
Were almost there.
The skill of reading the temperature by the colour of the steel alone.
Is this skilled blacksmith really able to do this?
The Japanese Knife blacksmith, Tatsuo Ikeda.
He has said that by looking at the colour of the steel alone, he can judge the heat of the steel in increments of 5℃.
We have also used a heat monitoring device to properly read the outcome for ourselves.
The temperature monitor is on the left of the screen.
The steel has been inserted.  We will wait about 2 minutes.
We’re just about there.
800 now.
-800 now.  
-At this moment, the heat monitor device reads 799.9℃.  That’s a difference of 0.1℃.
Mr. Ikea successfully called out the correct temperature as it was dropping.
800 now.
Mr. Ikea successfully called out the correct temperature as it was dropping.
800 now.
On the nose.
By the ability to read the temperature this way, the Honyaki knife, a knife with remarkable cutting power was born.
A craftsmen that can understand the characteristics of steel can accomplish this through self-discipline.
It’s traditional technology, but at the same time, it’s very advanced.
However, no matter the blacksmith, it takes a daily devotion to create such a knife.
If you can do it, you simply do it.  Your eyes become more experienced.
However, no matter the blacksmith, it takes a daily devotion to create such a knife.
If you can do it, you simply do it.  Your eyes become more experienced.
Because of this, it took 10 years to see something that wasn't able to be seen before.   But no matter the trade, no matter the craft, it is the same isn't it?
It's a lifelong study.
Because of this, it took 10 years to see something that wasn't able to be seen before.   But no matter the trade, no matter the craft, it is the same isn't it?
It's a lifelong study.
Succeeding with skill and heart,  skills become more well honed.
The beautiful and glistening sword is an engravement of the soul of the blacksmith.
