Hello, I would like to do this simple transform, but and I am not able to figure this by my own.
My logic assumed that I should go and find something like this:
Filter -> Colors -> Black and white
But in the filter -> Colors menu, I can only see Color to alpha, Color Transfer, Mnimize Channel and Maximize channel.

Any tip on this?

UPDATE: Thanks to boud for the solution, you have to go Filter -> Adjust -> Desaturate

With black and white, do you mean remove all color, but keep shades of gray, or a real two-tone black and white? If the former, go to Filters/Adjust/Desaturate, if the latter, then I have to admit that Krita does not have a filter for that yet.

Thanks a lot, I wanted precisely that
About the option placement, if it really only affects color (forgive me if I'm wrong), couldn't i be moved to Filter -> Colors? I think that it would make more sense to the common users.