" Maai is keeping distance first and foremost."
I always thought Maai is being mindful/aware of distance.....Be interested in the literal translation.
For Mark and Robert. The topic of ma-ai and de-ai has had much said about it by various folk and maybe always will because it's a principle and when using principles more and more you get to notice more and more about them.
However, I will give you my basic simplicity in relation to what you say above.
Mindful/aware of distance....Yes, of course. To keep distance you had better be mindful and aware of what you are doing and why. It's no good just being aware of if you don't know it means 'keep' for example in which case you would see it means you have to move and maintain.
Now, as far as what the word means then its good to recognize it has the word 'ai' in it so it is something related to harmony. Ma means space. Maintaining a harmonious space.
Many point out another point which is to do with distance, which circularly is space, but is explained this way....striking distance. The distance of taking one step and being able to strike the opponent. When talking about fighting distance it may be best to translate that as striking distance to see what ma-ai is from that perspective. Either way the basic is space and the circle.
In life you are aware whilst walking around when someone gets too close to you, when they cross that line, when they enter your personal space. Ma-ai. This shows there is a boundary and so if you get more expansive on the subject and apply it to communications for example you will see maintaining the boundary of harmonious communication keeps a good space. As soon as someone gets personal or aggressive etc. then that too breaks ma-ai.
De-ai brings time and place into the equation and is to do with motion. So this would include harmonious positioning and also harmonious connection in motion. That's why some call it timing. I call it harmoniously staying with.
So that's a few concepts from me on the matter.