Doriki is a unit of measurement used by CP9 to directly determine someones level of physical power. As such, it also allows one to estimate the power of their Rokushiki. In the Viz Manga and FUNimation dub, it is called Power Level.
According to Jabra, Doriki only measures someone's physical power and does not take into account the powers granted by Devil Fruits, despite that some Devil Fruits' (especially Zoan-types) directly increases someone's physical strength. No more details were given on how a Doriki measurement could be distorted.
It seems that Rob Lucci, Kaku, and Jabra are the top three members of CP9 (coincidentally, they are the three human Zoan types in CP9, despite Devil Fruit powers not being taken into account), as their Doriki are all drastically higher than the others, ranging in four-digits above 2000. It also seems that early on, Jabra had the highest Doriki of all of CP9 (then overtaken by Rob Lucci and Kaku); he also commented that he had never heard of a number as high as 4,000 before Rob Lucci.
Nero, the new recruit who was dismissed for failure, never had his Doriki given, but Lucci declared him not to be worthy of being a CP9 member, with his Rokushiki training being incomplete, mastering only four techniques. Out of all the CP9 members, Spandam holds the lowest fighting ability—vastly beneath those of the trained assassins who were under his command. At a measly 9, Fukurou noted Spandam's Doriki confirmed he was even weaker than a guard.
Known Doriki Levels
- Rob Lucci: 4000
- Kaku: 2200
- Jabra: 2180
- Blueno: 820
- Kumadori: 810
- Fukurou: 800
- Kalifa: 630
- Common armed Marine soldier: 10
- Spandam: 9
- One Piece Manga and Anime — Vol. 40 Chapter 379 (p. 7+10) and Episode 266, Fukurou uses te-awase to calculate the Doriki of the CP9 members, and gives reference about a common soldier and Spandam's Doriki.
- One Piece Manga and Anime — Vol. 40 Chapter 385 (p. 8-9) and Episode 271, Jabra thinking the potential effects a Devil Fruit power may have on Doriki calculations.
- One Piece Manga and Anime — Vol. 40 Chapter 379 (p. 8) and Episode 266, Jabra is surprised he's been overtaken by Lucci and Kaku.