Nico Robin haki kick color by xMrNothingx on DeviantArt

Rokushiki + Haki Robin action scene storyboard by Shinjojin on DeviantArt

The Nico Robin: Rokushiki Style Project

Tekkai, One Piece Wiki

In One Piece, why do the members of CP9 learn to use the “six powers”, but not haki? - Quora

Was Rob Lucci's Rokuogan an application of the advanced Haki that Luffy is learning now? - Quora

One Piece: Strongest Abilities That Are Not Devil Fruit Or Haki

One Piece: 6 poderes mais fortes que não são Haki

Queen of the Damned — I'm guessing that Robin does know some form of

One Piece: Rokushiki Explained - How Strong Was Rob Lucci & CP9? (The Six Powers)

Why aren't there more characters who uses Rokushiki? Like if you spend your whole life being a swimming champion only to have to eat a Devil Fruit that throws away those years