| A samurai's sword is his most sacred and prized | | | | the steel, as well as the steels impurities would be |
| possession. Not only did the samurai rely on his sword | | | | spread throughout the whole of the sword, |
| to defend him, but spiritually the sword held greater | | | | therefore strengthening it in its entirety. When the |
| significance as the samurai actually believed his soul | | | | blade came to be cooled it wasn't simply quenched in |
| inhabited the sword. Therefore it comes as no | | | | water, another process had to be done first. When |
| surprise that the same discipline and respect in which | | | | steel is been cooled, if it cools from a high |
| the samurai wielded his sword, went into the actual | | | | temperature right down to cold in a short amount of |
| making of the sword itself. | | | | time, the metal becomes very hard and brittle. |
| Swords weren't simply 'cast' in a mould and then | | | | Conversely, if steel is cooled slowly from a lower |
| sharpened. A Japanese samurai sword was made by | | | | temperature right down to cold, the steel takes on |
| an intricate process of heating the steel, hammering it | | | | more supple, even softer properties. Because a |
| flat, then folding it, then hammering it flat again, and | | | | samurai sword was used primarily as a slicing weapon |
| folding. This process of repeated hammering and | | | | the blades were subjected to a lot of shock upon |
| folding would be done up to as much as 30 times, or | | | | impact on the enemy, therefore the blade couldn't be |
| until the maker was satisfied it had been done | | | | made of the more brittle steel throughout else it |
| properly. | | | | would shatter like glass. But the sword had to retain |
| There are quite a few reasons for this labour-intense | | | | its sharp edge, so it couldn't be made of softly |
| procedure. Firstly, any air pockets which might | | | | forged steel throughout else it would simply blunt. So |
| develop during the heating of the steel would be | | | | a balance was struck using a very clever procedure. |
| eliminated. Having an air pocket in a seemingly solid | | | | What the Japanese samurai sword makers |
| blade would be a weak point, and any weak point | | | | discovered was by painting on a clay formula onto |
| would be seen as neglect and any dedicated artisan | | | | the blade before quenching, thin amounts onto the |
| would produce the highest quality blades as if his own | | | | cutting edge and thicker amounts onto the back, the |
| life depended upon the very blade he was forging. | | | | steel could be made to take on two completely |
| Secondly, in the repeated folding and hammering, | | | | separate properties, thereby giving the blade the |
| what might be described as 'layers' were produced. | | | | hard cutting edge it required, and the more supple |
| Take a book and roll it up it parallel with the spine, | | | | back. Because of the different speeds in which the |
| these internal layers would look something like this, | | | | two halves of the steel cooled this also formed the |
| almost like the rings of a cross section of a tree | | | | beginning of the curve from which the sword makers |
| trunk. This added much strength to the blade. | | | | would work to create the famous curved blade. |
| Also the natural strengthening carbon elements within | | | | |