Friday, August 5, 1966, is the day this chronicle likes best, because on it the scene's defining rivalry played out two rooms and a few blocks apart, each with its own poster. That night the Family Dog opened a weekend at the Avalon Ballroom with Big Brother and the Holding Company — Janis Joplin's band, the Avalon's own — sharing the bill with Oxford Circle, under Stanley Mouse and Alton Kelley's FD-19, the poster collectors have long called the "Dollar Bill" for its currency-parody design, with Bill Ham on lights. The very same Friday, across town at the Fillmore Auditorium, Bill Graham countered with Love — Arthur Lee's pioneering Los Angeles band — and Everpresent Fullness, on Wes Wilson's BG-21. Two houses, two poster shops, two bills, one night: the Family Dog and Bill Graham running head to head, which is the story of 1966 in miniature (both bills are documented on chickenonaunicycle's Fillmore and Family Dog lists and corroborated on Wolfgang's for catalog number, designer, and date).

The "Dollar Bill" carries a small trap worth handling honestly, and it is the kind the poster catalogs invite. FD-19 prints a four-act lineup — Big Brother, Oxford Circle, Bo Diddley, and the Sons of Adam — but those acts never shared a stage. FD-19 is a two-night Avalon poster, and the Family Dog was running a second room at the same time on a second poster, FD-20 (also Mouse and Kelley). Laid out by night, the weekend runs like this. Friday the 5th at the Avalon: Big Brother and the Holding Company with Oxford Circle, on FD-19. The same Friday at Longshoremen's Hall: Bo Diddley with the Sons of Adam, on FD-20. Saturday the 6th at the Avalon: Bo Diddley and the Sons of Adam again, back on FD-19. And Sunday the 7th at Longshoremen's Hall: Bo Diddley and the Sons of Adam once more, with Little Walter added, on FD-20.

So the two sheets interlock rather than duplicate: FD-19 holds the Avalon on Friday and Saturday with a different headliner each night, while FD-20 holds Longshoremen's on Friday and Sunday, with the Avalon night sandwiched in between. Bo Diddley plays three of the four. We keep each poster's billing as the artifact records it, and note that August 5's Avalon stage specifically belonged to Big Brother and Oxford Circle.

This is also the source of a persistent cataloging muddle: because FD-19 genuinely does advertise Bo Diddley — on its Saturday side — casual sources tag FD-19 as the Bo Diddley poster and appear to swap the two numbers. There is no swap. Every museum-weight record agrees: FD-19 is the Avalon, FD-20 is Longshoremen's. Big Brother in early August 1966 were still a local band with a national breakthrough ahead of them — a year before Monterey — and seeing them headline the Avalon on a Mouse-and-Kelley poster is the Family Dog scene at its most self-contained and confident.

Against that, Graham's Love booking is the perfect foil: an out-of-town headliner (Love were an LA band, and Arthur Lee one of rock's genuine originals) at the Fillmore, drawing the same crowd the Avalon was courting, the two promoters splitting the city on a single Friday. The Love run went August 5 and 6; the Fillmore's more famous benefit — Quicksilver, Big Brother, and the Grateful Dead among a long list — came the day after, August 7, and is a separate story.

The later years give August 5 a run of real but secondary shows, and one honest gap worth naming. In 1967, August 5 was a Saturday in the middle of the Fillmore Auditorium's Muddy Waters / Buffalo Springfield / Richie Havens run — the BG-76 booking already anchored on its August 1 opening. In 1968, August 5 was a Monday one-night special at the Fillmore West that is a small landmark of its own: Ornette Coleman, the architect of free jazz, playing a Bill Graham room. The piece survives in the catalogs as AOR-2.80, filed among the "unusual Fillmore shows," its lettering laid over a page of Coleman's own score; the designer is given as "Dore" on the catalog listing we could reach, but the attribution is thin enough that we flag it for confirmation rather than state it flatly. In 1969, August 5 opened a Fillmore West run — Paul Butterfield with It's a Beautiful Day and SRC — on David Singer's BG-185, and that poster has the strangest footnote of the lot. It was booked as a Grateful Dead and Fleetwood Mac double bill, and both headliners fell through. Fleetwood Mac's name stayed on the printed sheet, which is why catalogs still file BG-185 under their name for a show they never played. The Dead's name did not: it had made it onto the poster, and Singer had to take it off at the last moment, so every surviving copy carries a blank where they used to be. Butterfield and It's a Beautiful Day filled the hole. It is a printed record of a show that did not happen as designed — and of the correction, still visible. Only 1965 is a true blank: the scene did not exist yet.

Five Augusts, then, but August 5 belongs to 1966 — Big Brother at the Avalon and Love at the Fillmore, Mouse-and-Kelley against Wes Wilson, the Family Dog against Bill Graham, the whole competitive engine of the ballroom scene running on a single Friday night.