|— Rob Lucci, CP9.|
The Rokuogan is the secret and ultimate attack of the Rokushiki style. Rob Lucci states that only those who have absolute mastery of the other six skills can have access to this seventh skill.
The user places both their fists right in front of the target to focus their physical strength to launch a devastating shock wave in a forward direction. The burst is a reminiscent of that released by an Impact or Reject Dial, capable of bypassing the defenses of a rubber human such as Monkey D. Luffy, who is highly resistant to blunt strikes under normal circumstances, and causes massive internal injuries. This is only used during desperate situations as Lucci is always shown panting after using it.
- Rokushiki Ogi: Rokuogan (六式奥義 六王銃 Rokushiki Ōgi: Rokuōgan?, literally meaning "Six Styles Secret Skill: Six King Gun"): Used by Lucci. This is the ultimate Rokushiki technique that can damage an opponent internally, similar to the Impact Dial, or of equal or more strength to the Reject Dial, but the technique is considered to be much more powerful, and can be performed without the side effect of great pain to the user. It appears to be two fists held at close range that can damage the opponent with a blast powerful enough to cause even Luffy to cough up blood and come close to death. While used only in his "Shaved" Human-Beast Form, the proportions to his human body are roughly the same and can be assumed that he could use it otherwise. This is proven in Pirate Warriors 3, where he only performs it in his Human Form. In the Viz Manga, this is called Six Powers Supreme Six King Pistol. In the FUNimation dub, this technique was originally called Six Powers Extreme: Six King Pistol, though later uses of the move called it Six Powers Extreme: Six King Gun.
- Sai Dai Rin: Rokuogan (最大輪 六王銃 Sai Dai Rin: Rokuōgan?, literally meaning "Maximum Ring: Six King Gun"): Used by Lucci in his Human-Beast Form, it is his strongest attack. He wraps his tail around the target to restrain them from escaping before performing Rokuougan, except now with a larger attack radius and greater attack power than normal due to the enlarged fists of the Human-Beast Form. In the anime, the resulting shock wave can shatter rock even after going through its intended target, and in Episode of Merry, the shock wave punched a hole in the wall behind Luffy. In the Viz Manga, this is called Ultimate Radius: Six King Pistol, while in the FUNimation dub, this technique is called Ultimate Radius: Six King Gun.
- The Rokuogan resembles the One Inch Punch, which generates tremendous amounts of impact force at extremely close distances. It was invented by Chinese martial artists centuries ago and popularized by Bruce Lee in 1964.
- One of the most advanced applications of Busoshoku Haki is very similar to Rokuogan in practice. It involves the user infusing their own Haki within an opponent or object's body, destroying them from the inside through a close-ranged shockwave. Just like Rokuogan, this specific technique is quite rare and difficult to master.
- One Piece Manga and Anime — Vol. 44 Chapter 425 (p. 15-16) and Episode 308, Lucci uses Rokuogan against Luffy.
- One Piece Manga and Anime — Vol. 44 Chapter 426 (p. 17-18) and Episode 308, Lucci's second use of Rokuogan on Luffy tires him out.
- One Piece Manga and Anime — Vol. 44 Chapter 427 (p. 10-11) and Episode 309, Lucci uses Sai Dai Rin: Rokuogan against Luffy.
- One Piece Anime — Episode of Merry, Lucci's Sai Dai Rin: Rokuogan punches a hole in the stone wall behind Luffy.