The photo was taken at the 2008 10th international Aikido congress, where there was also an exhibition in Tanabe with relics and photo's of O Sensei's life. Most of what was shown came from the Kumano Juku Dojo. This bokken was unusual big and heavy, more like a suburito.
What is the specific detail that you are looking for?
Sorry I'm late with the response,
I'm very glad that someone still knows more about this bokken, and thank you for share that information with me and others.
Somehow I felt that was a little bigger bokken, because that I make my replica a bit "gained" in relation to other aikido bokken that I usually make, you could see more pic. on my aikido buki blog, if you interested I could send you this replica, just live me PM
ah yes, about details we could discuss also on PM