Why are samurai swords curved?

Japanese samurai sword originated in China during the Tang dynasty Tang Yokai, in the Sui and Tang dynasties, Japan does not have their own knife technology, entirely through imitation and learning Chinese knife technology to produce swords, in the Tang dynasty, has sent more than ten batches of Tang envoys to China to study, many of which were Japan's skilled craftsmen at the time, they brought back to the Tang Yokai knife knife-making skills in Japan, after imitation gradually Formed the present Japanese samurai sword, Japan Shosoin collection of a fine Tang sword, very precious, is regarded as Japan's national treasure, the samurai sword with its excellent performance in the world of cold weapons occupies an absolute position and enjoys the best reputation and honor.

It is curious, since it is imitated the Chinese Tang Dynasty Tang horizontal sword, but the Japanese sword and the Tang sword is the biggest difference is that the curved curvature, in this regard, many people have questions, why the Japanese sword made into a curved. How did the curvature of the samurai sword come about? On this topic is also a lot of discussion ah!

Based on the above questions, there are several statements.

1, the cause of the curvature of the samurai sword is due to the production process of the Japanese sword, in the clay burnishing stage due to the blade part of the blade covered with something, so the temperature is not the same as the back part of the sword, quenching due to the thermal expansion and contraction of the metal caused by the Japanese sword curved.

2, the Japanese sword is improved on the basis of the Tang sword, in view of the era of Japanese men 1 meter 5 tall, the length of 1 meter 1 straight Tang sword is inevitably not suitable for drawing and swinging, over time it bent.

3Some say it was due to the fact that Japan did not know how to heat treat the blade, in addition to the fact that it was not well learned at the time.

From the point of view of today's modern thinking, this is not the case, the Japanese sword is designed to bend curved arc has its own characteristics.

First: the blade is curved behind the back, when chopping, it will automatically correct the direction, the closer the contact point is to the tip of the blade, the more obvious, to enhance the killing power.

Second: back to the knife, inertia on the knife rotation, easier to turn the blade 180, and the rotation process, the center of gravity continues to move, the hilt swing is basically stopped, than the straight knife, "hard to stop, and then cut back" to be easier. This is more obvious in the Mongolian machete, Arab machete.

But I don't know whether this process is due to do so inadvertently found more suitable for chopping or know that the curved knife chopping up the effect and intentionally do so, I personally tend to think that is the knifemaker in order to pursuit of the high hardness of the edge of the part of the knife and produce inadvertent action.

In fact, today it seems that these issues have been unimportant, because the art is not divided into borders, but an art is inadvertently found, for craftsmen to speak of a traditional forging techniques is the need to continue, but also a kind of wisdom of the ancients it is necessary to continue to combine the different times of the continuation of the different follow up, which is the persistence of the craftsman has been pursuing each, perseverance, Careful craftsmanship.