Sengoku Strays(2007)

Sengoku Strays

Kasane is your average kendo-obsessed girl, when a brush with a mysterious sword sends her back in time to the Sengoku Era. Stuck in an unfamiliar time and place, Kasane also has the poor luck of winding up right in the middle of the turmoil that surrounded Oda Nobunaga's rise to power!

(Source: Storm in Heaven)