September 8, 1965 is the quietest date in this window and, for that reason, one of the most interesting: it predates the poster scene almost entirely. There was no Fillmore dance yet (Bill Graham's first was still three months off) and no Avalon (it opened in April 1966). What there *was* was the Matrix — the small club at 3138 Fillmore that Marty Balin had opened on August 13, 1965 essentially as a house room for his new band, Jefferson Airplane. On September 8 the Airplane were playing it, with JC Burris, the harmonica player and nephew of Sonny Terry, on the bill (concerts.fandom.com; tourarchive). The documented residency runs across September 1, 2, 3, 8, 9 and 10; I'd treat the exact per-night details as community-sourced rather than archival, but the residency itself is well attested — this is the Airplane in their own room, weeks before the ballrooms they'd help fill even existed. There is no poster; there wouldn't have been.

By 1967 the same calendar day was thick with posters. At the Fillmore it was night two of the Byrds' BG-82 run (see September 7). At the Avalon, Greg Irons's FD-80 opened — Southside Sound System, Phoenix, and Freedom Highway (wolfgangs.com FD080). And in Denver, the Family Dog's very first show opened the same weekend: FD-79, also catalogued FDD-1, Rick Griffin's poster, with Big Brother & the Holding Company (Janis Joplin) over Blue Cheer and Eighth Penny Matter (concertposterauction; en.wikipedia.org/wiki/The_Family_Dog_Denver). That last one is out of town — Denver, not San Francisco — but it's the scene exporting itself, Chet Helms's Family Dog planting a flag in the Rockies, so it earns a place on the day as an adjacent event. In 1968, September 8 was the closing night of the Avalon's FD-136 James Cotton weekend (see September 6).