Ryou and hardening are the same thing, both are CoA
As for the sparks they aren't a sign of hardening. You can see several panels of Zoro with smoke and hardening but no trails
I have several other panel
As for the sparks they aren't a sign of hardening. You can see several panels of Zoro with smoke and hardening but no trails
The scabbards and zoro have shown multiple times that you can use ryou and then harden your blade
The tiny spark has only ever been hardening
No coc user has ever had coc lightning that tiny ever in the manga
You have no argument