It is a bit of an irony that I had to return on family related matters. Not that it matters much, I got my two weeks in, but this is the second occasion my woodworking plans have been nearly thwarted by public sector work actions this summer, but still, I am in total sympathy
It's fantastic that you got some first hand recommendations for yari kanna use and maintenance but it seemed the members from Japan were traveling with a bare minimum in tooling, very understandable, so no yari kanna that I noticed, just like the Scandinavians all with their very versatile, light weight and transportable Gransfors Bruk hewing axes, (with the exception of Martina's huge side axe, and then Magnus hauling that frame saw back on the roof of the van).
Luckily I had no run-ins with food poisoning and in fact thought we were very well cared for by the Bohmsholz hosts. I too noticed the difference in the French and German work routines, mainly that the Germans wait till the end of working before taking their alcohol, very sensible even if somewhat boring.