Friday, August 19, 1966 is the rival-twins night at the very beginning — before Fillmore West, before the Avalon's fame had set, when the two rooms were still learning the weekly rhythm that would define the era. At the Fillmore Auditorium, Bill Graham hung BG-24: the Young Rascals — the blue-eyed-soul hitmakers of "Good Lovin'," visiting Eastern pop royalty — over Quicksilver Messenger Service, the local guitar band still two years from a record. Wes Wilson drew it, one more in the astonishing fourteen-month run of posters he was producing at nearly one a week (per wolfgangs, which dates BG-24 to Aug 19 and credits Wilson). A mile away that same night, Chet Helms's Family Dog answered at the Avalon with the "Frankenstein" poster, FD-22 — see that entry.

The Young Rascals had come a long way to play a room like this. They were a New York band — Felix Cavaliere, Eddie Brigati, Gene Cornish and Dino Danelli, out of the Long Island club circuit by way of the Barge in Westhampton — and "Good Lovin'" had gone to number one that April. In the summer of 1966 they were a genuine chart act in a way almost nobody on the San Francisco bill circuit yet was, and they were also, still, four young men in matching knickerbockers and Little Lord Fauntleroy collars, a costume their manager had put them in and which sat oddly in a ballroom where the audience had stopped dressing for anything.

Quicksilver Messenger Service, beneath them, were the opposite proposition: no record, no manager of consequence, no national profile, and a live reputation in this city that was already formidable. John Cipollina's guitar — the tremolo, the long sustained bends — was a local sound before it was a recorded one. They would not release an album until 1968. On this night in August 1966 the visiting hit-makers were on top and the band that mattered locally was underneath, which is exactly the arrangement the next two years would invert.

Wes Wilson drew BG-24 in the middle of the most productive stretch any poster artist in the series ever had — roughly a poster a week through 1966 and into 1967, inventing as he went the lettering that would define the form. It is worth remembering how compressed that was. Wilson's entire Fillmore run lasted about fourteen months before he and Graham fell out over money and he walked away, and nearly everything anyone means by "psychedelic poster" was worked out inside it.

A mile away the same night, Chet Helms's Family Dog answered at the Avalon with FD-22, the "Frankenstein" poster. That was the rhythm the two rooms had already fallen into by the late summer of 1966: two halls, two posters, two bills, every weekend, each watching what the other booked. Neither had been running a year.