From Wikipedia:
Checkmate is an American detective television series starring Anthony George, Sebastian Cabot, and Doug McClure. The show aired on CBS Television from 1960 to 1962 for a total of 70 episodes and was produced by Jack Benny's production company, "JaMco Productions" in co-operation with Revue Studios. Guest stars included Charles Laughton, Peter Lorre, Lee Marvin, Mickey Rooney and many other prominent performers.
The series chronicled the adventures of a private detective agency set in San Francisco. Created by Eric Ambler, the program involves the cases of the detective agency called Checkmate, Inc. Don Corey and Jed Sills run the agency, which specializes in preventing crimes before they happen, from Corey's stylish apartment, supposedly at 3330 Union St. Sebastian Cabot portrays a Ph.D. college professor whom they employ as an adviser. Dr. Hyatt's dachshund Bismarck also appears occasionally. Ken Lynch is frequently seen as police dept. contact Lt. Thomas Brand.
The series was a critical favorite. Many exterior scenes were shot in San Francisco. In 1961 John J. Lloyd won the show's sole Emmy nomination for Outstanding Achievement in Art Direction and Scenic Design. The icon for this series is swirling liquid shapes at the opening and closing of each episode with theme music.
The series aired on CBS on Saturday in the 8:30-9:30 PM time slot from its début on September 17, 1960 until June 24, 1961. The series was a hit that season, finishing at #21 among all series. It was then reprogrammed to Wednesday in the same time slot from October 4, 1961 to June 20, 1962, where it fell opposite The Perry Como Show on NBC. CBS replaced it with The Beverly Hillbillies.