Ill be in nagano this year, mostly nozawa onsen I think. If anyone is in the area let me know and I'll put you on a board ;-)
The thought process behind the hammerhead shape came to me last year as I studied the behaviour of all the swallowtail and the birdman. I noticed how the wide nose of the birdman seemed "better" than the pointy nose of my swallowtail due to more surface area so i went one better with this design by maximising the surface area of the nose as much as possible.
When I drew the shape I started with the sidecut radius as usual and then flipped the radius template around which gave me the nose shape