You may have heard it said that the Germans love their rules, and the country's favorite TV show is no exception.  For half a century it's been a Sunday evening tradition to sit down after dinner and watch Tatort, Germany's beloved whodunnit.

There are, predictably, also certain "rules" that make up the ritual TV event.

1. The opener

It's 8:15 pm on a Sunday evening in Germany. Just after the evening news show, Tagesschau, the opening Tatort jingle rings in countless households across the country. It's a melody that practically everyone — even those who don't necessarily watch religiously each week — can hum along to.

Less well known is that the tune was written by Klaus Doldinger and has only been modified — ever so slightly — twice since it was first heard when the show was launched in 1970. The accompanying geometric cut-out graphic screams "70s" and would make anyone cringe — if it weren't such a classic. It has really been the only constant in every single episode since 1970.

2. The tradition

1970. That means Tatort has been around for 50 years. The only show that's had a longer run on German television is the so-called "Wort zum Sonntag," or "Word for Sunday." In Germany, public broadcasters are required by law to give the Catholic and Protestant state Churches a short but regular broadcast platform for a brief weekly message.

Tatort, in any case, is the longest-running crime show in German-speaking Europe: It launched in Austria in 1971 and has been running with a few interruptions in Switzerland since 1991.

3. Local color

Each week, Tatort is set in a different region in Germany. Sometimes it's in Hamburg, or in Cologne or Berlin. But smaller towns like Saarbrücken and Ludwigshafen also get their turn on screen. In neighboring France, on the other hand, practically every crime show is set in Paris or Marseille, which has a reputation for being dangerous.

Tatort is a product of Germany's federal system. Not only do various cities make an appearance, but the federal public broadcaster ARD is divided into regional entities and the production of each episode rotates among them. And, of course, they all take advantage of the opportunity to throw in a bit of local color. In the Cologne Tatort, for example, detectives Freddy Schenk and Max Ballauf never miss a chance to enjoy a currywurst and Kölsch beer at a stand on the Rhine River. In Dortmund, on the other hand, Peter Faber prefers Pilsner and French fries at the harbor.

4. The snack bar

Snack bars are as essential to Tatort as ketchup is to French fries. While the American officers in the CSI series (which, by the way, also mixes up the locations, even if there are only three: Miami, New York and Las Vegas) discuss their cases in bars, their German colleagues go to the local snack bar to talk. From bratwurst to fries and beer, none of them seem particularly interested in staying healthy.

5. Das Auto

Apart from the snack bar, the Tatort detectives also love to think through their cases by chatting in the car — Germans' favorite means of transportation. While Karl-Friedrich Börne, the arrogant and overly intellectual pathologist in Münster, drives a sports car, Klara Blum from Lake Constance prefers a C-class Mercedes. Freddy Schenk from Cologne has a classic American car that serves as the butt of many jokes, while Peter Faber in Dortmund relies on his trusty Saab 900. The message is clear: Das Auto is not just part of the German soul, in the case of the Tatort detectives, it's also a window to their souls.

6. The detectives

The Tatort detectives are a colorful bunch, none is like the other. Most, however, are more anti-hero than hero or heroine. They tend to be single-parents working through failed relationships (not unlike their colleagues in Swedish crime series); they have crooked teeth and bulging bellies and an embarrassingly awkward gait when chasing after speedy suspects on foot.

It's immediately obvious that these characters would never turn up in American, French or Italian crime shows, where the detectives tend to resemble models and athletes.

Female detectives are well represented on Tatort and make up about half of them — without an official quota ever being introduced. Investigation teams are often male-female duos — and the vast majority of the detectives are well over 40.

7. Twitter frenzy

You shouldn't be surprised to see a recurring trend on German Twitter each Sunday at 8:15 pm. As the old school jingle sounds, the frenzy breaks loose: To follow along, the hashtag is simple: #Tatort.

The show's official Twitter account, @Tatort, has nearly 240,000 followers. It was counting down the days ahead of the 50th anniversary broadcast:

   

8. Share the experience

It was during the 2006 soccer World Cup in Germany that Germans started the practice of watching sport events in large groups. They even gave it a word that sounds like it's borrowed from English: Public-Viewing.

Like a football match, Tatort has been enjoyed in pubs for many years. Drinking beer and speculating over the murder has become such a beloved past-time that some pubs even specialize in Tatort showings. Even faithful fans want to complain about the quirks of the detectives or the style of the production — and that's more rewarding when there's someone around to agree with you.

Unfortunately, the 50th anniversary will have to be celebrated in lockdown mode. Some groups have been setting up online meetings to compensate — but that's a lot of screen management.

9. The social dimension

Produced by public rather than private broadcasters, Tatort is not purely about entertainment, but also about encouraging dialogue over current social issues. Hot-button topics like forced prostitution, drugs, racism, refugees, and German's asylum policies are often dealt with in the show. The pressing relevance of the issues at hand spurns the discussion online and in real life. German talk show host Anne Will has a broadcast slot just after Tatort and sometimes picks up a topic related to the episode.

10. The Tatort seal of approval

Facts have to be checked. That's not only true about the facts in Tatort — which aren't always true (the public prosecutors keep at cases their real-life counterparts would never take on) — but also the facts about Tatort. A dissertation has actually been written about the representation of corpses in the popular show and different books about Tatort have been published, including a new one that celebrates the 50th anniversary with a series of little-known and bizarre facts. And that fits nicely with the 50-year-old tradition.