[Zu Ra]

ISSHIN=KAIEN

NO =)

Spoiler:

1. Ichigo is constantly compared that he has a lot of similarities with Kaien (both looks & some character traits). I think it’s normal to assume Isshin should have looked something like his son before.
2. Both have black hair (Isshin & Kaien I mean)
3. Both have that weird thingy on the nose
4. I don’t think the time when Kaein actually “died” is given (I didn’t find), so 20 years might be a possibility. (might be wrong with the timing, I’m not sure) (Here it says Rukia is about 150 years old, so it is possible
5. He IS supposed to be dead, but with Urahara as “back-up” I wouldn’t be surprised ~_~

To begin with there is absolutely no connection between Kaien and Ichigo in terms of Isshin . BLEACH UNIVERSE BELEIVES IN REINCARNATION . When a Konpakku dies its rein carnated and goes back to living world .

Also just google Nirvana if you have any doubts regarding Nirvana and min 7 reincarnation prinicples, and Shinto has lot of common practise with budhism . WE can only speculate Ichi is re-incarnation of Kaien . And thats what Kubo leads us to beleive . Dont get Isshin mixed up here .

Who is Isshin ?

Spoiler:

IMHO he was a seated shinigami who aided Urahara's escape and thus was banished from Siereitei . And yes the Masaki's maiden name being Kurosaki makes lot of sense. Kudos on that theory

The only puzzling thing is

Why were his powers sealed away , he does say to Ryuuken my shinigami powers have returned