A swordfight story taking place in Edo era (17th - 19th century). Yasuri Shichika is the seventh head of the Kyotou school of Japanese sword martial arts and lives in Fushou Island with his sister Nanami. With the order from a female samurai general Togame, he sets out for a trip to collect the twelve treasured swords created by a legendary swordsmith Shikizaki Kiki.
It was already announced that an anime based on Nishio's another light novel "Bakemonogatari" will be produced by Shaft.
This news will be updated when the larger version of the cover note is available.
Edited on Dec 1st=========
Kodansha website has a little bit larger image. It reads "Details will be given in January 2009." A "Nishio Ishin Anime" website opened and it's counting down for something. The countdown is due to end on January 1st 2009.