Context: Someone at my dojo injured his left fingers. Nothing too serious but his doctor advised him to not to grip anything for a bit. He came to practice and used his right hand only to lift his shinai above his head like he's doing katate jodan.

I always assumed, that since in Kendo most of the power comes from the left hand, katate jodan would be done exclusively done with left hand and doing it with right hand would not be valid. When I asked him politely after practice (he's higher rank than me), he just shrugged his shoulder and said, "Sensei doesn't seem to mind, better than waiting for my left fingers to heal".

Which gets me to wonder: is migi katate jodan (右片手上段) a valid kamae?