Changes

We do know that in the 5th century steel swords were already made in Japan.  

We do know that in the 5th century steel swords were already made in Japan.  

These were of the straight, single-edged type called '''Chokuto'''.  

These were of the straight, single-edged type called '''Chokuto'''.  

The method of hardening the steel that is so typical of Japanese swords was  

The method of hardening the steel that is so typical of Japanese swords was first used in 6th century.  

first used in 6th century.  

Very ancient sources as the '''Kojiki''' and the '''Nihon Shoki''' already  quotes swords as highly valuable weapons and objects of worship. This is confirmed by the number of swords found in '''Kofun''' and the high number of swords which belongs to Shrines.  Its debated how many activities were visualized with the ancient polishing methods but is undeniable that, in early times, the beauty of the Japanese sword was only  caused by the pursuit of its practical functions as a weapon. Already in the VI century b.C. we have the insurgence of a Japanese taste in fittings but the design of the blades was still strongly influenced by the continent, being the fighting tactics equally imported from China and mainly based on masses of footsoldiers with spears and shields.  There is an old saying regarding Japanese swords: Orenai, Magarani, Yoku Kireru (shouldn't break, shouldn't bend and cuts well). These are the most important qualities a sword must have and Japanese swordmakers ('''Tosho''') made great efforts in searching for improvement of the Chinese specimens. When these tactics changed due to the fight against '''Emishi''' for domain of the '''Kanto''' plain, the advantages of a curved sword for horseback fighting begun evident to the japaneses, that already showed their attitude to practicality and skillfullness in adopting foreign items adapting and upgrading them to their needs. As long as the original purpose of the sword is of a practical nature, it is natural that changes of fighting style and cutting targets have influenced the sword, especially in the shape. For this reason we can judge the approximate age of the sword  

Very ancient sources as the '''Kojiki''' and the '''Nihon Shoki''' already  quotes swords as highly valuable weapons and objects of worship. This is confirmed by the number of swords found in '''Kofun''' and the high number of swords which belongs to Shrines.  Its debated how many activities were visualized with the ancient polishing methods but is undeniable that, in early times, the beauty of the Japanese sword was only  caused by the pursuit of its practical functions as a weapon. Already in the VI century b.C. we have the insurgence of a Japanese taste in fittings but the design of the blades was still strongly influenced by the continent, being the fighting tactics equally imported from China and mainly based on masses of footsoldiers with spears and shields.  There is an old saying regarding Japanese swords: Orenai, Magarani, Yoku Kireru (shouldn't break, shouldn't bend and cuts well). These are the most important qualities a sword must have and Japanese swordmakers (Tosho) made great efforts in searching for improvement of the Chinese specimens. When these tactics changed due to the fight against '''Emishi''' for domain of the '''Kanto''' plain, the advantages of a curved sword for horseback fighting begun evident to the japaneses, that already showed their attitude to practicality and skillfullness in adopting foreign items adapting and upgrading them to their needs. As long as the original purpose of the sword is of a practical nature, it is natural that changes of fighting style and cutting targets have influenced the sword, especially in the shape. For this reason we can judge the approximate age of the sword  

from the '''Sugata''' (Shape) as well as '''Jihada''' and '''Hamon''', that are strictly related to functionality.

from the '''Sugata''' (Shape) as well as '''Jihada''' and '''Hamon''', that are strictly related to functionality.

Is generally agreed that the fully developed Japanese sword appearance was around the 940 a.C., period in which we find the most ancient extant swords with all the characteristics needed in the "ideal" japanese sword : single edge differentially hardened with strong curvature. Some of these ancient blades already shows another peculiarity of the japanese sword : a softer steel inner core wrapped by harder steel. It's debated if all such ancient blades are made the same way, but at least some shows that this technology was already used in this period. As this “basic” shape has changed in its key features many times and quiet deeply during the centuries, we need to know the periods in which the history of the japanese sword is divided in.

Is generally agreed that the fully developed Japanese sword appearance was around the 940 a.C., period in which we find the most ancient extant swords with all the characteristics needed in the "ideal" japanese sword : single edge differentially hardened with strong curvature. Some of these ancient blades already shows another peculiarity of the japanese sword : a softer steel inner core wrapped by harder steel. It's debated if all such ancient blades are made the same way, but at least some shows that this technology was already available and used in this period. As this “basic” shape has changed in its key features many times and quiet deeply during the centuries, we need to know the periods in which the history of the japanese sword is divided in.