Condensed history lesson coming up, quiet at the back there!.
This series represents a real life incident in which the Samurai
of a young lord who had to commit seppuku,
vowed revenge on the lord who they saw as responsible for his dishonor and death.

They actually split up for a long period before re-uniting
and attacking the fortress of said lord,
they won the day and had their revenge loosing only
one of their own in the fighting.

The ruling Daimyo at the time had a problem,
congratulate them for holding true to the
Samurai ideals or have them executed for their crimes.
They elected to allow the samurai to take their own lives
which in honour tradition, they did.

No matter what, I think that deserves respect.
That's the short version,
for one of the expanded version try
it will open a new window.