Rokushiki + Haki Robin action scene storyboard by Shinjojin on DeviantArt

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

Why didn't Luffy learn Rokushiki techniques? - Quora

Rokushiki and Haki THEORY : r/WildAnimeTheories

Rokushiki is better than haki : r/Piratefolk

What if Rokushiki is Haki based?

Vivre Card Databook – Index Set (some new information) – The Library of Ohara

Nico Robin haki + rokushiki by xMrNothingx on DeviantArt

Which do you prefer in One Piece, Devil Fruit, Haki or Rokushiki? - Quora

Chapter Discussion - Rokushiki is based on Haki, Page 7

15 Things You Didn't Know About Haki In 'One Piece