The Sword Arts are the shinigami's oldest and in fact the first means of offence they had against the hollows. Back then the shinigami fought with regular katanas rather than the zanpakutos of today. At the time, every shinigami knew the way of the Sword Arts and the teachings demanded total mastery of the sword and complete adherence to the Seiretei's old codes of honor and discipline. There is even a legend about how the first shinigami used the sword arts to defeat the first espada. These teachings were said to have been lost thousands of years ago, not long after the introduction of zanpakutos. However, a certain captain happened upon an ancient scroll containing the secret and thought to be lost teaching of the sword arts. Thus the Seiretei has yet another weapon with which to repel the hollows.