Also known as: 森中花咲(高校制服), 森中花咲(5万人記念衣装)
The fourth costume of Nijisanji's Morinaka Kazaki, as seen in post #4132905, and her second to use her 15-year-old self as the wearer.
It is a high school outfit, consisting of a Black Serafuku, a Red Neckerchief, a Pink Cardigan, black Pleated Skirt, baggy white Socks, and brown Loafers.