Thanks for everyone's comments.
Tom I believe Sadaharu Oh himself called it a flamingo
stance in A Zen Way of Baseball
but I no longer have a copy. It's a good read.
On the slightly different point of moving on a plane of course the plane does not have to be parallel to the ground although it often is. It can be slightly upward or slightly downward depending on the movement and the intention.
If you believe that going forwards means simultaneously going backwards I wish you luck. You obviously need it.
The idea that Morihei Ueshiba didn't speak of ka without mi is nonsense. Ka is a letter of the Japanese alphabet as well as a word in Japanese with several meanings. It is used in hundreds of compound words that do not contain mi.
I think that Mark's referring to things like:
Of course, this is harder to portray in romaji - but there are hundreds of examples of this kind of usage in "Take Musu Aiki" and other places.
Forward without going backward is (I assume) in reference to the Chinese Mao Dun Zheng Li (矛盾争力, opposing force pairs) - which Ueshiba also referenced in "Take Musu Aiki" and other places.