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The Lethal Blades of the Past: GoT for Engineers

Valyrian Steel Swords

This is the third article in our exploration of the material world of A Song of Ice and Fire, more familiar to us as the Game of Thrones. Make sure you read:

For years, Tywin Lannister begged the lower houses of Westeros to sell him their Valyrian swords.

After all, how could the Lannisters claim to be a great house without one of these prized steels? The Starks had Ice, the Tarlys had Heartsbane, the Mormonts had Longclaw and even the Corbrays had Lady Forlon.

Tywin too wanted a lasting ode to his legacy. A gleaming sword with its distinctive patterns, like ancient runes drawn on grains of wood.
The Houses replied that they would happily marry off their daughters to Castle Rock, but would not part with a family heirloom as priceless as a sword made of Valyrian steel.

Oathkeeper is one of two Valyrian steel longswords made from Ice, the greatsword of House Stark, under orders of Lord Tywin Lannister.
Oathkeeper is one of two Valyrian steel longswords made from Ice, the greatsword of House Stark, under orders of Lord Tywin Lannister.

The Lannisters did once have an ancestral sword of their own: the Brightroar. However, Tommen II Lannister lost it on his doomed expedition to the ruins of Valyria. Neither the Lannister nor his sword were ever found.

Then Ned Stark died (murdered by the blonde haired Joffrey, born of incest) and the Lannisters took hold of Ice. At the time, only a few Qohorik swordsmiths knew how to reforge Valyrian steel. And, as luck would have it, one of them lived right in King’s landing – master armourer and blacksmith, Tobho Mott.

Brienne of Tarth with the Oathkeeper
Brienne of Tarth with the Oathkeeper. Credit HBO

Ice was reforged into two blades – the Widow’s Wail, presented to King Joffrey on his marriage, and the Oathkeeper, which would eventually end up in the hands of Brienne of Tarth.

The Inventories

What is more tragic is that no one knows how Valyrian steel was made.

It is generally assumed that dragons had something to do with it. Magic was said to be involved. Some have even suggested dragon blood.

It is not just swords, however. The crown of Aegon the Conqueror was a ruby studded glory cast from Valyrian steel. It has not been seen since the days of the eighth Targaryen king, Daeron I Targaryen.

The Inventories, written by Archmaester Turnbull lists 227 articles in Westeros made from Valyrian Steel, some of which have since disappeared. It is not known whether the crown is on this list. If found today, it would probably be more expensive than the seven kingdoms put together.

Barring this one crown, Valyrian steel seems to have been exclusively used for making swords and daggers. This is hardly surprising; no other metal has its unique combination of strength and flexibility. Valyrian swords are unbelievably strong, light, easy to carry, never lose their sharpness and are unbreakable. Castle-cast steel, by comparison, is a heavy stick of iron, routinely breaking in battle and needing constant maintenance.

But, no less awe-inspiring were the swords wielded by Saladin the Victorious or the samurais of ancient Japan. These swords were strong and flexible. Some of them had patterns on their surface. A few were said to be so flexible that you could bend it around your waist, and still have it spring back to its original shape.

The art of sword making

For most of our history, sword making was as much an art as it was a science. The principal reason for this was the huge variability in the quality of steel available to swordsmiths.

Depending on the type of ore, the quality of the kiln, the nature of the fuel, humidity, etc. the type of steel obtained varied drastically from region to region. It would take our combined knowledge of twentieth-century chemistry to identify that these deviations were due to the presence of carbon at the time of smelting or forging.

Senior blacksmith forging the molten metal.

Much like salt in water, carbon dissolves in iron. Iron with low carbon content (less than 0.08%) is a flexible metal that is not particularly strong. Higher carbon content in excess of 2% changes it into a tough metal that is also brittle. What is today called steel falls in between these two extremes.

However, precise control of this carbon content was not technologically possible until the industrial revolution in the eighteenth and nineteenth centuries.

To read more about the development of the different kinds of steel read “The iron throne and steel swords“.

The sword of the samurai

Over a millennium ago, the Japanese samurai swordsmiths developed the Katana swords by ingeniously solving the carbon-in-iron problem.

The steel that they still manufacture is called Tamahagane which literally means ‘round and precious steel’. The starting material is a very pure iron sand found in Shimane, Japan. This is heated for three days in a large clay tub filled with alternating layers of iron sand and charcoal. Here is a full description of the process of Tamahagane forging. 

What results is an inhomogeneous black and grey blob of metal. The dark parts are high in carbon and brittle. The grey is relatively pure iron and flexible. The master can identify and separate each type of iron by visual inspection alone.

The genius of the Katana is that it is literally one type of iron wrapped in another. The heart of the sword is a single piece of flexible low carbon iron. This is covered with high carbon steel. The soft core allows the sword to be flexible and agile. The hard outer covering withstands impact and can be polished to a sharp edge.

While forging, the iron is repeatedly folded in on itself and beaten, which produces a distinct band-like pattern on its surface.

It was said that a good Katana sword could cleave a man in half from head to toe with a single stroke.

The swords of Damascus steel

Perhaps no steel is as legendary as Damascus steel. In 1191, Richard the Lionheart met Saladin the Victorious in the battle of Arsuf somewhere in present-day Palestine. In a prewar show of power, Richard withdrew his massive sword and struck a thick piece of iron that promptly broke apart. Undeterred, Saladin withdrew a thin narrow dagger from his waist, tossed a silk pillow into the air and sliced it in two before it landed on the ground.

Saladin had with him a dagger made of Damascus steel that would soon be fabled all across Europe. Despite the smallness of stature and the seeming fluidity, it was a lethal weapon capable of cleaving its enemy without losing its edge.

Damascus steel dagger
Damascus steel dagger by Studio Blade (

Like Valyrian steel, the swords made of Damascus steel had distinct grainy patterns on their surface by which they could be recognised.

Once again, it is not entirely clear how these swords were made. Most historians, however, think that the steel used for sword making came all the way from India.

Parts of South India and Sri Lanka produced a kind of steel known as ‘wootz’ that was highly prized during the middle ages. To make wootz steel, the craftsman melted iron and materials that contain carbon – such as charcoal, wood or leaves – in a specially designed crucible. The steel that came out was in the form of a cake the size of a hockey puck. The wootz cakes were then shipped to Damascus, where smiths made them into blades.

To shape the cake into a blade, the smiths repeatedly heated and hammered it until it was stretched and flattened into a blade shape. As the metal was heated and beaten, the wavy pattern somehow formed on the surface of the blade.

We now know that it is the presence of a small amount of Vanadium that causes these patterns to form. Vanadium hastens the formation of tiny particles of iron carbide which are visible only under a microscope. The repeated hammering causes these particles to band along stress contours in the blade. This is what we see as the grainy patterns:

Recently, several researchers have reported the presence of iron carbide nanowires and carbon nanotubes in specimens of ancient Damascus blades. Carbon nanotubes, as the name suggests, are single-atom-thick tubes of carbon atoms that have become known only in the last two decades. It was therefore quite shocking to discover these exotic materials in ancient steels.

It is not quite clear how they were formed or what effect they have on the final blade. It has been suggested that the presence of these nanoparticles alter the microstructure of steel, causing some particular phases to preferentially form over others.

Carbon and cementite nanostructure in Damascus steel [3].
Carbon and cementite nanostructure in Damascus steel [3].

Scientists are hopeful that studying these ancient steels can shed new light onto creating lightweight high-strength steel.

If so, it may not be long before we boast of our own Valyrian Steel.

I work in the cutting edge area of applying machine learning and artificial intelligence to one of the earliest endeavours of human civilization - in understanding, exploiting and developing new materials.

*This article is the work of the guest author shown above. The guest author is solely responsible for the accuracy and the legality of their content. The content of the article and the views expressed therein are solely those of this author and do not reflect the views of Matmatch or of any present or past employers, academic institutions, professional societies, or organizations the author is currently or was previously affiliated with.

* These images were taken from Game of Thrones, or from websites created and owned by HBO, the copyright of which is held by HBO. Images are used for educational purposes only. 

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