The 47 Ronin

From Shambhala:

In the eighteenth century, forty-seven samurai avenged the death of their master in a plot that would take over two years to complete. After succeeding in their mission, the masterless samurai—known as ronin—all committed ritual suicide. The story, which is a national legend, remains the most potent example of Japan's deeply rooted cultural imperative of honor, persistence, loyalty, and sacrifice.