Rokushiki + Haki Robin action scene storyboard by Shinjojin on DeviantArt

One Piece: All Known Rokushiki Abilities, Ranked

One Piece Gold - Rob Lucci's vivre card said that: The training required for the acquisition of rokushiki is akin to that used for acquiring haki. Akin = in the family Rokushiki

The Rokushiki Techniques Explained

Rokushiki Martial arts styles, Island arc, Luffy

Powers & Abilities - Who used haki and who not?

One Piece 1081: Strongest Haki users in One Piece updated ranking

Powers & Abilities - New Level CoO + CoA Combination Technique..

Chapter Discussion - Rokushiki is based on Haki, Page 3

Would you rather have a strong Devil Fruit or strong Haki/Rokushiki? - Quora

ROKUSHIKI ACTUALLY HAKI POWER- Yaps, - Mugiwara Dangers