421-a will-

 is the fourth single by KOTOKO.

CD

 * 1) 421 -a will-
 * 2) Shuusou (秋爽)
 * 3) 421 -a will- (Original Karaoke)
 * 4) Shuusou (秋爽) (Original Karaoke)

Limited Edition DVD

 * 1) 421 -a will- PV
 * 2) 421 -a will- Making