Haki/Busoshoku Haki

Busoshoku Haki allows the user to create a force similar to an invisible armor around themselves. Similar to Tekkai, this Haki allows the user to defend against attacks that would otherwise cause them harm. Significant physical force can still overcome this defense; for example, Luffy struck Boa Marigold hard enough with Gear Second techniques that it sent her reeling.

Background
It was used by Garp for the first time against Luffy to bypass his Devil Fruit power and hurt him in Water 7. Later, Sentomaru used a Haki-imbued attack against Luffy, which made the Straw Hats think he was a Devil Fruit user due to their lack of knowledge about the ability. Afterwards, Rayleigh used Haki to stop Kizaru and even touched his Logia body. The first time the Kujas named this ability "Haki", they were shown wielding Haki-imbued arrows. During the Marineford War, Haki was also used many times by marines and pirates alike. It was shown that Haki is very common in the New World, unlike in Paradise where Haki users are fairly rare and almost nobody knows about it. It is later explained by Rayleigh once he begins training Luffy.

Usage
Naturally this "invisible armor" can be used as a weapon to strike others with. It can be used to augment the user's own attacks, projected ahead of the user as pure brute force, or imbued in weapons to increase their effectiveness. Any attack enhanced by Busoshoku Haki hits immensely harder than it would normally be without it. The Kuja's Haki-imbued arrows, for example, are capable of penetrating solid stone.

This type of Haki also has the ability to bypass the powers of a Devil Fruit user, touching the "substantial body" beneath whatever protection the fruit provides, such as the case of body-altering Devil Fruits such as Logia or Paramecia users. However, unlike Kairoseki, it does not negate a user's Devil Fruit powers, allowing them to defend themselves, and continue fighting normally. By the same effect, this Haki can also be used as a higher level of offensive power, more so than just bypassing a foe's Devil Fruit powers.

A heavy concentration (or coating) of this Haki can be used to harden parts of one's body, turning the area black, thus making the user denser and more formidable, and giving their attacks greater power. Although Luffy, the first in the mainstream storyline to demonstrate this effect, named the technique as Busoshoku: Koka (武装色 硬化), Donquixote Doflamingo is the only other person to use this name for the technique.

Busoshoku Haki works independently of the user's Devil Fruit, as shown when Luffy uses it to enhance his Gear Third attack underwater. This type of Haki may not be equipped to attacks that are not from one's body except for weapons, or anything generated from one's own body (like Kizaru's laser beams, Marco's flames or any other energy/non-solid attacks based on Devil Fruits). So, those who attack with parts of their body can combine their Haki and Devil Fruit powers.

Drawbacks
Devil Fruit users who can use Haki can resist the effects of Haki-imbued attacks, Akainu was able to take Haki-imbued attacks while maintaing his intangibility by extending his Haki through his body in order to nullify his opponents bypass. This however depends on their level of mastery over Haki when compared to their opponent as can be seen when Akainu was in contrast harmed when attacked by Whitebeard's superior Haki and bled. Later, although Vergo imbued his entire body with hardened Haki, which nullifies the powers of Devil Fruits, Law bypassed his Haki and bifurcated him easily by using his Devil Fruit technique. It is unknown if Law used Haki to nullify Vergo's Haki but it is similar to how Akainu was able to nullify it. Additionally, when two opponents using Busoshoku Haki clash, the one with the stronger Busoshoku Haki is more likely be victorious.

Techniques

 * Busoshoku: Koka (武装色 硬化): This technique somehow uses Busoshoku Haki to harden the body (or parts of it) and objects which the user is holding. It was first seen used by Monkey D. Luffy, in combination with Gear Third, in order to use his "Gomu Gomu no Elephant Gun" against the Kraken. When a body, body part, or object is hardened, it becomes black and has the same or stronger effect than the invisible application of Color of Armaments. It is implied that Hardening is stronger than the invisible application as the characters who are able to use Hardening are not seen utilizing the invisible application. When both hardened fists clash, it releases a massive shockwave and black-lightning like effects. So far Luffy, Vergo, Smoker, Zephyr, Chinjao, Garp, Sabo, Jesus Burgess, Donquixote Doflamingo, Trafalgar Law, Bellamy, Sai, Roronoa Zoro, and Pica have been seen using it. Zephyr had earned the nickname "Black Arm" because of his mastery of it. It can also be imbued into weapons, as Vergo utilized it on a bamboo stick, Smoker on his Nanashaku Jitte, the latter indicating Busoshoku Haki can be used in conjuncture with Kairoseki, and Zoro on his swords. Also called Buso Koka (武装 硬化) by Luffy when he uses an advanced form of "Gomu Gomu no Gatling" and simply Buso (武装) by Doflamingo when he blocked Luffy's attack. In the Viz Manga, it is called Color of Arms Hardening and FUNimation subs, it is called Armament: Hardening.
 * Atama Buso (頭武装): Used by Luffy, he imbues his forehead with Busoshoku: Koka to harden it. This is first used in preparation for a Gomu Gomu no Kane against the Iron Shell Squadron. In the FUNimation subs, it is called Head: Hardening.
 * Gear Second Buso (ギア2（セカンド）武装): Used by Luffy, he imbues his fist with Busoshoku: Koka while under the effect of Gear Second to harden it, which also seems to have the added effect of igniting it. It was first used in preparation for Gomu Gomu no Red Hawk against Hody Jones. In the FUNimation subs it is called Second Gear: Armament.

Translation and Dub Issues
The Kōka in Busōshoku: Kōka can also translate as "vulcanization", which is the process of rubber (or similar substances) being converted into a denser material.

Trivia

 * Busoshoku Haki is similar to Tekkai. The difference between them is that Tekkai depends on the user's physical strength, but Busoshoku Haki depends on the user's willpower. Also, while Tekkai is more inclined to defense, with the user usually being immobile while tightening their bodies, Bushoshoku Haki does not have such a drawback.
 * Busoshoku Haki users can still utilize their Devil Fruit powers, despite Haki being able to negate Devil Fruit abilities. This is because Haki only allows the user to bypass defenses provided by other peoples' Devil Fruit powers. In fact, Devil Fruit users can use the two abilities together to make one or the other more effective.
 * Busoshoku Haki is the most used type of Haki in the series so far.
 * Although the black skin effect of its usage is pretty common after the timeskip, it was not seen at all before, not even during Summit War Saga, where many pirates and marines of the highest level participated. The reason for this is currently unknown.

Site Navigation
Haki/Haki de l'Armement Haki/Busoshoku_Haki