On page 5 of this document: http://www.moj.go.jp/ONLINE/IMMIGRATION/16-1-1.pdf

It has spaces for Self Supporting or Remittance from outside of Japan, wouldn't a family member's bank statement and signature be enough there? or even a friend's if they're willing to sign it and attach their banking info? i mean it's on immigration's own form and all!

the only evidence i have in my interest in cultural activities is fairly anecdotal stuff. i have correspondence dating from 2004 or 2005 with a swordmaker but i don't want to move all the way down to kansai to learn smithing just yet.

how do people who want to study ikebana or bonsai here on cultural visas prove they want to study if they weren't florists or horticulturists or something before? the best i can do right now is show that i have made some garments before on a sewing machine, i have some old websites online i created dedicated to the research of japanese martial arts, and i have some people who will vouch for the fact that i attended their martial art lessons. pretty slim pickings.