That uniform, if it existed at all, only lasted for about a year. Evidence suggests that the Shinsengumi in fact wore NORMAL clothing, not the blue and white we generally think of. If they did wear such an outfit, we're not even sure it was blue and white. It may have been yellow and white, the colors of Aizu. Serizawa always had that certain flair for the dramatic... I don't think it's all that simple...