First of all thank you for your comments, I really appreciate it.
I was a bit confused regarding the date Steve, because I found two different dating methods: Showa (1926) +14 - 1 = 1939 and 1926 + 14 = 1940 (Southern Nengo method). Probably the experienced collector knows the difference for me it was making a guess at that moment.
John, it was an informed decision and I always ask myself when selling something: will it change my life drastically. In this case it isn't. The memories of my grandfather will always be with me, with or without the sword and beside that specific era there's fortunately more to tell about him.
It's a true piece of history, for some to collect for others not...finally it's just a matter of interest!
Hopefully there will be a collector who I can make happy with this sword and not just a gardener who will use it to chop his hedges...