Is Haki visible to other characters?


We know of the several forms of Haki, the Kenbunshoku Haki, Busoshoku Haki and
the Haoshoku Haki. I've been wondering, are those Haki visible to other
characters in the One Piece universe, or only visible for the reader?

And I am mainly interested in the Busoshoku Haki, as this seems to harden the
body and makes the skin look metal like. Can people in the One Piece universe
also see this metal like change? Or is this just for the viewer to
differentiate between normal fighting and Haki fighting?




From the moment Rayleigh explained to Luffy (and to us) what Haki really is, I
believe that every single time Busoshoku Haki is used, Oda draws visual cues
for the reader to know it has been used, but it doesn't actually change color
in the OP universe. Mainly to prevent too much speculation from our point of
view.

The [Busoshoku Haki wiki
page](http://onepiece.wikia.com/wiki/Haki/Busoshoku_Haki) in a way confirms
this by explaining Busoshoku Haki as an _invisible_ armor.

> Busoshoku Haki allows the user to create a force similar to an **invisible
> armor** around themselves.

Therefore I believe that when Busoshoku Haki is used, the object does not
really change colors in the OP world. Not much real proof could be found to
the visual changes of Busoshoku Haki except for maybe the fight between Zoro
and Monet. When Zoro slashed Monet, both Monet and Tashigi thought the slash
was coated in Haki, which it wasn't in the end. So to me that means that the
characters can't distinguish Busoshoku Haki usage with visual cues as we can.
They can only distinguish it from the after-effect.

[![enter image description
here!](https://i.stack.imgur.com/dfPFnm.png)](https://i.stack.imgur.com/vO2MY.jpg)

**Edit:** Actually after thinking about it some more, the fact that Oda didn't
draw Busoshoku as black before the time-skip would proof that it doesn't
actually turn black in the One Piece universe. **If it would, wouldn't he have
drawn it from the beginning**? One could argue that the Koju tribe's Haki
wasn't as powerful enough to be turned black, but I doubt someone would
disagree on this with _Dark King_ Rayleigh. The moment he blocked Kizaru he
must have needed some powerful Haki to block that kick and yet it still didn't
turn black. Other examples can be seen during the Marineford arc with Marco,
Whitebeard, Shanks, etc.

[![enter image description
here!](https://i.stack.imgur.com/srt4Pm.jpg)](https://i.stack.imgur.com/srt4P.jpg)

* * *

Contra to what I have said earlier and I'm not sure whether this would be
considered canon, but I'll mention it anyway. In [Volume
1000](http://onepiece.wikia.com/wiki/One_Piece_Volume_1000),
[Zephyr](http://onepiece.wikia.com/wiki/Zephyr) is nicknamed "Black Arm" for
his superior B. Haki usage. Nicknames are usually something you obtain within
the OP world as an OP character, so if you would consider Volume 1000, which
is a free volume distributed to One Piece Film Z's attendees, canon, then the
answer would be that the black color is indeed visible to people in the OP
universe.

[![enter image description
here!](https://i.stack.imgur.com/5oNUFm.jpg)](https://i.stack.imgur.com/5oNUF.jpg)

_PS: I don't speak Japanese and I think this is the picture the wiki referred
to, but could someone confirm what is written there?_




From the moment Rayleigh explained to Luffy (and to us) what Haki really is, I
believe that every single time Busoshoku Haki is used, Oda draws visual cues
for the reader to know it has been used, but it doesn't actually change color
in the OP universe. Mainly to prevent too much speculation from our point of
view.

The [Busoshoku Haki wiki
page](http://onepiece.wikia.com/wiki/Haki/Busoshoku_Haki) in a way confirms
this by explaining Busoshoku Haki as an _invisible_ armor.

> Busoshoku Haki allows the user to create a force similar to an **invisible
> armor** around themselves.

Therefore I believe that when Busoshoku Haki is used, the object does not
really change colors in the OP world. Not much real proof could be found to
the visual changes of Busoshoku Haki except for maybe the fight between Zoro
and Monet. When Zoro slashed Monet, both Monet and Tashigi thought the slash
was coated in Haki, which it wasn't in the end. So to me that means that the
characters can't distinguish Busoshoku Haki usage with visual cues as we can.
They can only distinguish it from the after-effect.

[![enter image description
here!](https://i.stack.imgur.com/dfPFnm.png)](https://i.stack.imgur.com/vO2MY.jpg)

**Edit:** Actually after thinking about it some more, the fact that Oda didn't
draw Busoshoku as black before the time-skip would proof that it doesn't
actually turn black in the One Piece universe. **If it would, wouldn't he have
drawn it from the beginning**? One could argue that the Koju tribe's Haki
wasn't as powerful enough to be turned black, but I doubt someone would
disagree on this with _Dark King_ Rayleigh. The moment he blocked Kizaru he
must have needed some powerful Haki to block that kick and yet it still didn't
turn black. Other examples can be seen during the Marineford arc with Marco,
Whitebeard, Shanks, etc.

[![enter image description
here!](https://i.stack.imgur.com/srt4Pm.jpg)](https://i.stack.imgur.com/srt4P.jpg)

* * *

Contra to what I have said earlier and I'm not sure whether this would be
considered canon, but I'll mention it anyway. In [Volume
1000](http://onepiece.wikia.com/wiki/One_Piece_Volume_1000),
[Zephyr](http://onepiece.wikia.com/wiki/Zephyr) is nicknamed "Black Arm" for
his superior B. Haki usage. Nicknames are usually something you obtain within
the OP world as an OP character, so if you would consider Volume 1000, which
is a free volume distributed to One Piece Film Z's attendees, canon, then the
answer would be that the black color is indeed visible to people in the OP
universe.

[![enter image description
here!](https://i.stack.imgur.com/5oNUFm.jpg)](https://i.stack.imgur.com/5oNUF.jpg)

_PS: I don't speak Japanese and I think this is the picture the wiki referred
to, but could someone confirm what is written there?_

