# Why is Kairoseki's effect more powerful than the sea?

It is said that the Kairoseki is just a solid form of the sea and have the same effect as the sea.

But why does Kairoseki weaken and negate devil fruit's power, like when a DF user is handcuffed or touched by it, it drains their energy and they lose their ability (Logias can't transform when handcuffed).

In case of sea water, I think it just drains their energy but never negates their ability (e.g. Luffy can still stretch to use elephant gun to knock out Kraken).

And is it ever shown or explained where the Kairoseki came from?

• looking at it from physics point of view, maybe because sea water has more surface area so the wavelength affecting devil fruit user gets dispersed easily. while kairoseki being solid with less surface area is able to affect more as it produces more concentrated wavelength so affects more. – Sp0T Mar 7 '14 at 5:38

Q. It is said that the Kairoseki is just a solid form of the sea and have the same effect as the sea.

Kairoseki is a naturally occurring (though apparently rare) substance that can cancel out Devil Fruit powers and weaken Devil Fruit users. It gives off a wavelength that is the same as the sea itself.

Q. But why does Kairoseki weaken and negate devil fruit's power, like when a DF user is handcuffed or touched by it, it drains their energy and they lose their ability (Logias can't transform when handcuffed).

In case of sea water, I think it just drains their energy but never negates their ability (e.g. Luffy can still stretch to use elephant gun to knock out Kraken).

When comparing two different things, the comparisons should be based on the same terms.

For example, you mentioned that Logia users can't transform when they are handcuffed with Kairoseki, but then, they can't transform when they are in sea either. So this example does not prove that Kairoseki is more powerful than sea.

Next, coming to the Luffy example (Paramecia type).

We know that both Kairoseki and sea weaken Luffy's strength, but we have seen that they do not cancel off his power, i.e. Luffy doesn't have enough strength to use his powers on his own. That is why the strength of his punch weakens when he uses the Elephant gun on Kraken as it goes out of the bubble and makes contact with the sea.

To make it even more clear, I'll give a better example.

When in Arlong park, as Luffy was about to drown in the water, Nojiko had to stretch Luffy's head out in the surface, to try to get him to breathe again. From this it is clear that a DF user (Paramecia type at least) only loses his strength and not his abilities even when under water.

The same way, when handcuffed with Kairoseki, Luffy loses all his strength and is unable to use his abilities by himself. We have not seen any case where someone tried to pull Luffy and was unable to because he was tied to Kairoseki. Thus, there is still a chance that even with the Kairoseki in direct contact with the user, their abilities can be made use of, but by somebody else, and not by the user themselves as they are totally drained out of energy.

Conclusion: This answer doesn't answer the question Why is Kairoseki's effect more powerful than the sea? directly, but rather provides some evidence to show why Kairoseki's effect wouldn't exactly be greater than the effect of sea on a DF user. I used two examples, that of a Logia and a Paramecia type DF user to compare and show the same. Thus the answer would have to be, No, Kairoseki's effect is not more powerful than the sea as we do not have any proper evidence to support such a claim. They both emit the same wavelength and thus, quite fittingly, have the same effect on the DF users.

Update: To support my answer even further, I found an interesting piece of information on the wiki page of Yami Yami no Mi. You can see that (emphasis mine)

The most unique and frightening advantage of the fruit is that the user also has the ability to nullify the powers of other Devil Fruits by simply touching the user and draining them of their abilities. All types of Devil Fruit, be it a Paramecia, Zoan or Logia, are affected by this, though Logias are most affected as they can no longer become intangible by transforming into their respective element. This nullification truly seems absolute, as though the Devil Fruit users had never gained their powers at all. This was shown when Luffy's stretching powers were canceled on touch, unlike the effect of a body of water or seastone, both of which just inhibit a person from controlling their powers. It was shown earlier when Luffy was stuck underwater that his neck could still be stretched above the water's surface, and that Busoushoku Haki would simply nullify the defensive aspects of a Devil Fruit such as intangibility and the malleability of rubber.

• I also remember a scene though im not sure if its canon since its from movie Z, where Luffy grabs Z on his arm when they saw him floating on the sea, Luffy is just weakened when but still stretched so i guess kairoseki does not absolutely cancels DF powers. – Nix R. Eyes Jun 27 '14 at 6:40
• @NixR.Eyes - I haven't seen the movie, so I can't comment on that, but if you do get a proper citation of that, feel free to add it in the answer. But as far as I know and remember, with what has been said and shown, neither Kairoseki nor sea water nullify the power. They just make the user very very weak to be able to use their powers on their own. – RainMaker Jun 27 '14 at 6:44
• Kairoseki Swords (like the one Smoker uses to Pound Luffy) Would not harm him if it did not nullify his power (which it did hurt Luffy youtu.be/Xy8RHMNOWZY?t=1m26s) Luffy does not need to control his powers for them to work, so something is missing here. – Ryan Mar 13 '16 at 7:06

Firstly Kairoseki is not solid form of sea
"It was stated by Vice Admiral Smoker that Seastone "gives off a wavelength that is the same as the sea itself" making him refer to it as a solid form of the sea".
Smoker was just referring kairoseki as solid form of the sea

It is a naturally occurring substance in the sea which was modified by Vega Punk and was used to make the handcuffs and other materials. (As per the wiki).

Something more from the wiki -
Weakness of devil fruit users

Devil Fruit users are susceptible to all types of water, not just seawater. This includes the white sea surrounding Skypiea. He elaborated on this, saying that "moving" water, like rain or waves, does not weaken Devil Fruit users, while standing water does. Oda also said in SBS that it is not until a Devil Fruit user is knee deep in water that they become immobilized, this is seen with the Gorgon sisters and Luffy in Boa Hancock's bath.

Why kairoseki affects so much?

Kairoseki, a special substance that emits the same energies of the sea, can also cancel out Devil Fruit powers through physical contact with the user. Depending on how much physical contact the users has with the Seastone, the more their movement is weakened.

• I don't think it answers my question. You just describe the water and kairoseki's effect on DF users. – Nix R. Eyes Nov 20 '13 at 1:52

To begin with. Kairoseki is a natural existent stone in the one piece world Although it is pretty rare quiet allot has been used in the form of handcuffs.

Kairoseki has been said to have the same effect as the sea but this is a bit dependent. Unlike the sea kairoseki is known to come in different desitys and compositions there for the effect of the handcufs might or might not be stronger then the say depending on the composition.

Just like the sea Kairoseki does not totaly negate a devil fruit user. It drains their energy slowly but surely they will be unable to do anything. There for it is possible for a devil fruit user to use his powers underwater aslong as he has some strenght remaining in his body and willpower might also have a bit of a effect on this. Although it still is a bit questionable there where some other exceptions where the user was still able to use powers in some situation.

However, it has been shown that though a Devil Fruit user loses his powers when in contact with the Kairoseki, said powers can still be used on the Kairoseki, as shown seen when Mr. 3's candle wax key could open Kairoseki cuffs and cell doors, though this may be because the locks themselves are not made of Kairoseki or because the wax has no Devil Fruit powers inside it as shown when he unlocked Ace's Kairoseki handcuffs. Another example is when Shiki levitated battleships in Marineford, despite the hulls being lined with Kairoseki. Trafalgar Law was also able to switch Kairoseki chains with regular ones, using his abilities.

Hope this covers most of your questions. Source Onepiece wiki

• trafalgar law didn't switch kairoseki chains using his power. he had mixed normal chains with kairoseki chains earlier. – Sp0T Mar 7 '14 at 5:18
• @sp0t so he switched them. Just like he said himself during his lockdown in the cage – Dimitri mx Mar 7 '14 at 10:21
• yeah but he was tied with normal chains not kairoseki one. so he can switch. but has he been cuffed with kairoseki chains, we don't know for sure whether he would be able to switch or not. – Sp0T Mar 7 '14 at 11:44

Kairoseki, as stated, "gives off a wavelength that is the same as the sea itself" (not the solid form of sea) and is used to somehow disable the devil fruit powers of the users (only when it is in direct contact with them). As for the story, it only stated that the devil fruit uses are completely rejected by the sea and just drown, nothing is mentioned about cancelling out the devil fruit powers.

Simply put, devil fruit users are afraid of the sea (immobilizes them), and kairoseki (cancels out their powers), and they emit almost same wavelengths.

As for the origin, nothing is mentioned in the story. Same is the case is with the Devil Fruits. They just exist in the One Piece's world like a natural thing.

As asked in the question, the effect only seems more effective because the user becomes incapable of using devil fruit powers, making the user completely normal human.

This however raises another question whether the devil fruit user will drown in sea while in contact with kairoseki, to which I would like to know myself.