A 13 episode anime series put out by Bandai. Yagyu Jubei
was Japan's greatest swordsman. On his deathbed, Jubei gives
his loyal disciple, Koinosuke Odago, a heart-shaped piece of metal
on a thong, the "Lovely Eyepatch"; he tells Odago that he is to
give the eyepatch to the successor to Jubei's school of
swordsmanship. When asked how he could identify the successor,
That's right, folks, plump, bouncy, and big ones ("Bonny boom boom
bum" in the original Japanese). You'd think that a woman like
that wouldn't be too hard to find in Japan, but Odago, through
sheer force of fanatical will power, searched and lived on for 300
years until he finds 8th grader Jiyu Nanohana, an ordinary modern
schoolgirl. Somehow Odago can tell that this particular
plump, bouncy, and well built girl is "The One", and begs her to
take the Lovely Eyepatch. Since she simply wants to be an
ordinary teenage girl, she never uses the damn thing unless the
villains are breathing down her neck, but since all of her teachers
seem to end up being the villains, this happens quite a lot. When
she dons the Lovely Eyepatch, she becomes Jubei-chan, an adult
version of herself with a cool uniform and a kick-ass sword.
(Although the eyepatch is a magical dohickey, and she goes through
a transformation when she uses it, this isn't a magical girl show, since she doesn't do any magic; she
just becomes unbeatable with a sword).
Ah, right, the villains. Thing is, when the original Jubei died,
there was a ninja clan with a rival style of sword fighting
that really wanted to defeat him, so they've been waiting
for the last 300 years for his successor to show up so they can
beat him/her. This clan also wants to take over the world, and
they want to posses the Lovely Eyepatch before they start the
conquering. This, I don't really get. Did the clan leader say
"Once I have the Lovely Eyepatch, I shall be invincible!
Muhahaha!"? *Sigh* Evil Overlords now-adays, they
simply don't have their priorities straight.