October 21, 1966 — the Grateful Dead headlined the Fillmore Auditorium, Friday and Saturday, October 21–22, with Lightnin' Hopkins and (as advertised) the Loading Zone in support. The poster is BG-32, a Wes Wilson design built around a Herb Greene photograph of the band — and it does double duty, because the same sheet also advertises a separate show the next afternoon: the Yardbirds and Country Joe and the Fish, Sunday, October 23 (per chickenonaunicycle, with the cross-promotion confirmed by poster-archive and auction records). The two posters of that weekend, BG-32 and BG-33, are a matched pair stitched together by one Wes Wilson sheet.

This is a deliberately pre-fame Grateful Dead. October 1966 is before "Anthem of the Sun," before even the first Warner Bros. album; the band had only lately moved into the house at 710 Ashbury that would become the Haight's most famous address. The lineup was the original five — Jerry Garcia, Bob Weir, Phil Lesh, Ron "Pigpen" McKernan, and Bill Kreutzmann (per jerrybase) — a local band playing a hometown ballroom, not yet the institution it would become. No setlist survives for either the Friday or the Saturday night; the record simply does not exist (jerrybase and dead.net both come up empty), so this page makes no claim about what was played.

The pairing with **Lightnin' Hopkins** is the night's quiet statement. Hopkins was a Texas country-blues songster, born in 1912 — roughly a generation older than the kids headlining above him — and his presence on a psychedelic ballroom bill is a clean example of a Bill Graham signature: booking blues and jazz elders onto the Fillmore's rock weekends, both because Graham's own taste ran that way and because it schooled a young white audience in where the music came from. A fifty-four-year-old bluesman opening for the not-yet-famous Grateful Dead is exactly the kind of juxtaposition the early Fillmore made ordinary.

The third slot carries a genuine ambiguity, and the honest thing is to name it rather than paper over it. The **poster bills the Loading Zone** — the Berkeley R&B-soul band — as the Dead's support. But a contemporary San Francisco Chronicle listing (Ralph J. Gleason's column of October 21, 1966) instead places the **Chocolate Watch Band**, the San Jose garage/proto-psych group, in that slot, and the correction is applied to both nights (per jerrybase, which cites the Chronicle; dead.net corroborates the uncertainty, hedging its own billing as "either the Loading Zone or the Chocolate Watchband"). So the advertised third act and the as-played third act may not be the same band. This page states the poster's bill and flags the discrepancy; it does not assert which group actually took the stage.

The weekday checks out — October 21, 1966 was a Friday, the 22nd a Saturday, the 23rd a Sunday — which makes this the opening of a Bill Graham weekend that ran Friday and Saturday with the Dead and then, as a separate "One Sunday Afternoon" matinee, handed the Fillmore to the Yardbirds (that Sunday show is BG-33, a story of its own two days on). There was also, that very weekend, a cross-town rival: at the Avalon, the Family Dog ran Country Joe and the Fish with the Daily Flash (FD-31, a Mouse-and-Kelley poster), Friday and Saturday — which means Country Joe played the Avalon on the 21st and 22nd and then crossed to the Fillmore for the Sunday matinee, a documented same-weekend double.

A note on context, offered as atmosphere and not as a claim about this show: California's ban on LSD had taken effect on October 6, 1966, just over two weeks before this Fillmore weekend — the legal line newly drawn under a scene that had grown up around the drug. (The BG-32 image itself is held in the classicposters/FAMSF catalog, unreachable headless; the facts here — the catalog number, the Wes Wilson and Herb Greene credits, the bill, the dates, the Chronicle wrinkle — come from the show-lists, the Dead databases, and poster-archive records rather than from the scan.)