The Fillmore West listing for Tuesday, September 9, 1969 reads, in its entirety: "Tuesday Night Jam/Audition."

No bill, no poster, no catalog number — an open night nobody printed anything for. Graham kept these on the calendar: unbilled sessions where local bands could play for a hearing, in the same hall that had Santana and Spirit on it earlier the same month.

It is worth having a page for one, because it is the negative space around everything else this chronicle records. The posters exist because a weekend needed selling; a Tuesday audition needed nothing, so it left a single line in a venue list and no artifact at all. For every David Singer photomontage there were nights when the room simply opened and let people play, and those nights are most of what a working hall actually does.

They also mattered practically. The Fillmore West's own bills through 1968 and 1969 are full of Bay Area bands — Cold Blood, the Loading Zone, the Sons of Champlin, Initial Shock — who had to be heard somewhere before they were booked. An audition night is where that happened.