The swords are often divided by age:
jokoto ("ancient swords") - 795
koto ("old swords") 795 - 1596
shinto ("new swords") 1596 - 1624
shinshinto ("new new swords") 1624 - 1876
gendaito ("contemporary swords") 1876-1953
shinshakuto ("modern swords") 1953 –
Oldest swords on record in Japan are the two that were sent as a present to queen Himeko from China during Wei-dynasty in 240 a.d. In 280 a.d. many more iron swords were imported from China to Japan. Katana is the most famous Japanese samurai sword.
Japanese Bushidoo

Bushido-Way of Warrior
Bushido Believes: Benevolence, Love, Sincerity, Honesty, Self-Control and Stocism.
Bushido had been developed in samurai society that started from the Kamakura period (1192-1333), and ripened at the Edo period (Tokugawa Shogunate era, 1603-1868).
Bushido is a strict code that entailed concepts such as loyalty to one's master, respect and self-discipline, overall ethical behavior.
Bushido comes from Buddhism, Zen and Confucianism.

1) The Buddhist concept of reincarnation and rebirth led samurai to abandon torture and needless killing, while some samurai even gave up violence altogether and became Buddhist monks after realizing now fruitless their killings were. Some were killed as they came to terms with these realization in the battlefield.
2) Zen meditation became an important teaching due to it offering a process to calm one's mind.
3) The most defining role that Confucianism played in samurai philosophy was to stress the importance of the lord-retainer relationship; this is, the loyalty that a samurai was required to show his lord. Confucianism is one of the three traditional Chinese religions. Here are some of the most important principles of Confucianism: Humanity, Loyalty, Morality and Consideration.

These different combinations of religions were brought together to create the one code of the Warrior known as Bushido. This code was considered to be very Confucian in nature.
A notable part of the Bushido code is seppuku, which allowed a disgraced samurai to regain his honor by passing into death, where samurai were still beholden to the rules of Bushido.