Originally Posted by apacolypz
You missed my point, you are making it sound like it is concrete that this is twenty years before though. Kubo could of easily said twenty years ago but he says in the not so distant past.
It just happens to be a few days before Masaki saved him from the same hollow that killed 3 other shinigami. Notice how Kubo started this flashback, with the after effects of a battle with a hollow that was strong enough to defeat a captain of Isshin's power (Toshiro pointed out that Isshin would've been held back had he (a young genius 3rd seat almost done with his bankai training) and Rangiku went along), then follows up with the events leading up to that starting point.
This is a slightly less shitty way of pulling off in media res
than Kishi did.