Thats a really nice decription...thank you. Well I found the only way to get of the wall I could see is when the body adjusts the spine and centre...the feet stay in position. It's hard to explain ^^ but I don't propel myself backwards. Actually there's no need to move imho...nothing needs to give.
Were you able to get off the wall?
What are you studying in Japan and where? Aikido, presumably. Karate? Judo?