Found it: 三日月極意
Google translate gives 'Crescent secret'
"Mikadzuki gokui".
If you translate the characters in blocks, you get
三=Three
日月=Moon
極意=Secret
The first 3 characters translate together
[1] as "Crescent moon" ("Mikadzuki"), and the last two to "Secret" ("gokui"). Gokui, however, is used in names such as Oozara Gokui ("Wingwalker", but literally "Big Cup Mastery"), so perhaps you could translate this trick name as "Crescent Mastery". However, I'm going to stick with "Banking", since it's quicker to say. :-)
Big disclaimer: I *don't* speak Japanese, but I feel like I "speak kendama" at least a little bit.
Although I very much like the explanation you gave for the trick name! You could have taken the easy road and call it 'Void's balance' :-)
That reminds me of a time at a juggling convention when someone was teaching us a silly game involving pointing fingers at each other. The person who was teaching the game was asked "What's the game called?". He paused to think about it, at which point Caspar (who was just learning the game) quickly and loudly said "
Caspar's game!".

So yeah, I'd be very wary of naming a trick after myself (or anyone, really) unless I was really sure I'd invented it.