The Shirofuku (白服, "white uniforms"), or Whiteshirts, are sword-bearing students of the highest rank, Rank S, and serve as Tenchi Academy's student council. Their name comes from the special white uniforms they wear, as distinct from the ordinary school uniforms, which are black.
Shirofuku do not participate in the Hoshitori, but have the unique privilege of being allowed to challenge (as a shinyuu pair) Amachi Hitsugi and Miyamoto Shizuku in a single duel for total control of the school. If this attempt is unsuccessful, however, the challengers drop out of the Shirofuku.
Tatewaki Hikaru wears a white uniform and is an official of the Student Council, but, as she is not a Rank S swordbearer, is not considered a Shirofuku.