IIUC (and with apologies to Grothendieck), Ishida succeeded at 3-dan with a fire spirit, overpowering his opponents. At 8-dan, however, the examiners are looking for the void spirit.
A fire spirit cracks a nut by using a hammer and chisel, striking as needed until the shell cracks.
A void spirit gets the meat by immersing the nut in a softening agent until hand pressure suffices to decorticate, like a perfectly ripened avocado.
Consider:
https://www.youtube.com/watch?v=DmLfnWwP0g0&t=280 (4:40 to 7:00)
IIUC (and with apologies to Grothendieck), Ishida succeeded at 3-dan with a fire spirit, overpowering his opponents. At 8-dan, however, the examiners are looking for the void spirit.
A fire spirit cracks a nut by using a hammer and chisel, striking as needed until the shell cracks.
A void spirit gets the meat by immersing the nut in a softening agent until hand pressure suffices to decorticate, like a perfectly ripened avocado.