When the chapter was first released, I doubted it was a black blade. But now I think it is indeed one, the white patterns in the middle is exactly how Oda draws Shusui
and swords coated in hardening
Ryokugyu :
It could just be active hardening, but the thing is that Ryokugyu isn't even holding the sword and it doesn't look like he has even used (or about to use it) either so that sounds pretty iffy
I'm not 100% on board about it being a black blade as one panel is not enough but from the look of it, it does seem to be one.
and swords coated in hardening
Ryokugyu :
It could just be active hardening, but the thing is that Ryokugyu isn't even holding the sword and it doesn't look like he has even used (or about to use it) either so that sounds pretty iffy
I'm not 100% on board about it being a black blade as one panel is not enough but from the look of it, it does seem to be one.