Ueshiba was very spiritual. Most all of his students admit that. Understand what he was saying or mostly what he was doing? No, mot so much understanding there.
Therefor it would be good to understand spiritual.
There arte many spiritual practices all over the world from yoga to all kinds of things and low and behold they tend to get various realities on the spiritual side of things. The first thing is that it's not an intellectual pursuit as with zen. You can intellectualize about it but that's different. Intellect is of the mind and so a mental thing. Spirit is not mind.
Spirit can perceive without need for any physical perceptic or mind. So perception without body or mind would thus be spiritual perception.
A nice zen perspective.