BERLIN  When “Law & Order” kicks off its new season next month, it will tie “Gunsmoke,” at 20 years, as America’s longest-running prime-time drama. Here in Germany, where a police procedural called “Tatort” has been around nearly four decades, 20 years can seem as ephemeral as a high school romance.

“Tatort” is a little akin to what Johnny Carson’s “Tonight Show” was in America. It’s one of those modest pop-culture symbols and long-standing common experiences that can be hard for outsiders to translate but that speak to, and of, a nation. First broadcast in 1970, before video games or food processors and when Germany seemed permanently split in two, the show adopted the age-old formula of a pair of detectives solving a murder to devise a distinctly German version of the crime drama.

Relatively speaking, violent crime isn’t common here. The killing of four people by a gunman who went on a rampage near Düsseldorf last week was all the more shocking for being exceptional. With a population of 82 million, Germany had 864 homicides in 2007; there were around 20 times as many in the United States, where the population is not quite four times as big.

Maybe that’s a reason “Tatort” (it translates as “Crime Scene”) plays down graphic violence in favor of character development and crime solving.