For decades, Ritter Sport has marketed its chocolate bars on their unique, square shape.

So when Swiss brand Milka challenged its German monopoly on square chocolate, the battle lines were drawn.

Milka achieved an initial victory in 2016 by getting the patent deleted but that ruling was overturned.

Finally, the case ended up in the Federal Court of Justice, where judges have now thrown out Milka's complaint and ruled in favour of Ritter Sport.

First, the history

The square bar dates back to 1932, when Clara Ritter came up with the idea, according to company legend. "Let's make a chocolate bar that fits in everyone's jacket pocket without breaking and weighs the same as a normal long bar," she is supposed to have said (although in German).

By 1970 it had come up with the slogan "Quadratisch, praktisch, gut" - quality, chocolate, squared, as the company likes to translate it.

The family company patented the shape in 1993, so when Milka began marketing a square bar in 2010, the case went to court.

Milka, now owned by Mondelez, won round one in the federal patent court but that ruling was later thrown out and the patent court decided the following year that Ritter could keep its three-dimensional monopoly.

Milka's final challenge in the Federal Court of Justice has now also failed.

What the judges said

Normally a brand cannot claim protection in Germany if its shape gives the product "an essential value". But the judges in this case said Ritter Sport was different.

Consumers considered the square nature of the chocolate bar as an indication of both where the chocolate came from and its quality, they concluded.

They said there was no artistic value to the shape and it did not lead to differences in price.

Their ruling means that the incumbent bar can remain the only top-brand square chocolate bar on the shelves in German shops.