actually there is a difference between Kuji Kiri and Kuji in. This I find seems to be forgotten. Seems like all think Kuji kiri and Kuji in as the same art but this is not true. Kuji Kiri is energy cultivation....and Kuji in is the Shugendo/Shinobi warriors energy channeling as I know.
me, I am still looking for the Kuji Kiri practise