Lots of interesting tidbits here: Isshin was the 10th squad captain back in his Gotei 13 days, with Matsumoto and Hitsugaya as his vice-captain and third seat, respectively. It seems like their characters were basically the same back then; Isshin was overly energetic and goofy, Matsumoto still had her enormous breasts, and Hitsugaya was the serious and hard-working genius. I would place this timeframe around a century prior to Ichigo’s time, as Aizen and his cohorts are still in the initial phases of their hollowification experiments (and of course, everything is still proceeding accordingly for him). It seems inevitable that Isshin will be caught up into these events, though I do find it strange that virtually no mention of him was brought up in the Turn Back The Pendulum arc. It may be that he does not leave Soul Society with Urahara and the other vizards at this time, but we’ll just have to wait and see.
In addition, Isshin’s original name is revealed to be Shiba Isshin, and as it turns out he was actually the head of the Shiba clan, meaning he was related to Kaien, Kuukaku and Ganju. It’s not clear if Kaien is still alive at this point, but if he is, his death may be revealed to have greater significance than we previously knew. Honestly, a lot more questions were raised than answered in this chapter, though that’s understandable since Isshin’s flashback is still in the “set-up” phase. No more mention of Masaki is made either, so the events this week felt rather disconnected from last week, and I’m really hoping that everything will be tied together soon.