In a related story:
I knew that a police station was next door (across a alley), but Kenny Barron opened my eyes this Summer on how it relates to the name of the club: Keystone Korner - Keystone Kops.
Todd is really out there!
It was a strip club/bar before:
"The Keystone Korner at 750 Vallejo Street opened in the late 1960's taking over from a bar/club which had operated in the same building. It became a rock venue in 1969 initially providing a weekly venue for Mike Bloomfield. It's popularity grew over the next couple of years at which time the owner, Freddie Herrera, took over a larger club in Berkeley which he named the Keystone Berkeley. The Keystone Korner was sold to Todd Barkan who turned it into a jazz club. It continued as one of the Bay Areas finest jazz venues until closing in 1983."
And:
"Freddie Herrera opened a club called the Keystone Korner at 750 Vallejo Street in San Francisco. The club was just a few blocks off of the "entertainment" district on Broadway. It had previously been a rock club called DenoCarlo's, and various local bands had played there in 1968, including a regular Monday night residency for Berkeley's Creedence Clearwater Revival. Herrera took over the club in 1969 and tried to make it into a topless dancing place, but it was too far from Broadway to capture the tourists and sailors. Fortuitously, Nick Gravenites wandered in, and he was looking for a club that he could use for various ends.
As a result, starting in mid-1969, The Keystone Korner became a rock club, often featuring various expatriate Chicagoans who had relocated to San Francisco, including Mike Bloomfield and Elvin Bishop. Bloomfield and Gravenites played there almost every other weekend from September 1969 through March 1970, and the little venue was sort of like their clubhouse."