Anniversaries mark the same place in the annular solar cycle. It's very ouroboros. Marking a new year is no less artificial and arbitrary than noting what makes a month a month or that "digital" is based on ten fingers. What's arbitrary is that that we chose January 1st instead of say March 1st.
43 years ago today, Jimi Hendrix played a series of shows at NYC's Fillmore East Theater in a power trio called the "Band of Gypsys." They hadn't performed together in public and this was sort of their unveiling. Note how Bill Graham introduced them: "...some old friends with a brand new name...a Band of Gypsys."
The Band of Gypsys more or less was just this set of shows—publicly at least. They were to play together just once more—later that month at the Garden where Jimi famously "lost it." After that, he broke with Buddy Miles and reassembled the Experience but kept his old friend Billy Cox on bass. They recorded a spring and summer of intense performances, but by September it was over—forever.
The call and response between Jimi and Buddy Miles in "Who Knows" is strikingly spiritual—imagine him doing that with Mitch Mitchell—not. Though it was already an established technique in American Blues with even deeper roots, it appeared anew and struck the same chord.
One more thing strikes me in that video: the way Hendrix flashes a brief smile through what must have been a painful time (1 min 9 sec). It's as if he realized the sheer joy of performing or perhaps he caught sight of an admirer. Elvis flashed a smile like that a few months before he too passed away: link
Here is 30 minutes of the same show: link The version of "Machine Gun" in that show is the definitive one.