Every German party is allotted its precise place in the political colour chart. It's like with identity cards: if a party doesn't have its colour, it doesn't exist. In coalition-culture Germany, colour tags provide voters with relief from the alphabet soup of initials that forms the standard diet of German politics.
Thus, red-black refers to a coalition between Social Democrats (SPD) and Christian Democrats (CDU), seen by some as the most likely outcome of the federal elections in three months' time. Or there might be a red-green coalition. Or there might be a traffic- light coalition - where Social Democrats and Greens get together with the yellow Free Democrats. (Sceptics about the Social Democrats' chances of ousting Helmut Kohl predict a black traffic light, come 16 October.)
Even fringe parties are allotted colours, so that they can legitimately be discussed. When the SPD in Hamburg formed a quasi- coalition with the newly-formed Instead Party - a respectable anti-party, whose political agenda involved not having an agenda - this was soon labelled the red-grey alliance.
So far, so almost simple - until the re-emergence of the former East German Communist Party, the PDS, as an important political force in the east. A new red-green minority government has just been approved in the east German state of Saxony-Anhalt, courtesy of the PDS. This is a small slice of history on its own account, and has caused indignation in the CDU, which claims that the PDS's initials stand not for Party of Democratic Socialism but for Partei des Schiessbefehls - the Party of Orders-to-Shoot. But the political excitement, which could affect the outcome of the election in October, may prove trifling, compared with the semantic confusion that has been unleashed.
Communists, and even ex-Communists or post-Communists, can reasonably expect to be described as red. Indeed, rote Socken or red socks, has become a familiar tabloid shorthand for the old-guard Communists. But red, minus the socks, is already the traditional colour of the SPD. How, then, to describe the PDS backing for Saxony-Anhalt's red-green coalition, while sticking to the compulsory colour chart?
The east German Wochenpost this month began experimenting with dark red, to describe the PDS, in Saxony-Anhalt. Die Woche uses a dirty purple, in its regular frontpage electoral barometer, in what the paper's political editor, Lutz Spenneberg, describes as an 'emergency solution'. But Mr Spenneberg sees the lack of an agreed colour for the PDS as 'a very practical problem'.
Gerhard Sporl, political editor of Der Spiegel, says that the problem is embarrassing, and argues: 'German unification has made the whole question of colour symbolism quite chaotic.'
One convenient solution would be if the SPD agreed to re-package itself as salmon-pink. But the party will not willingly give up the conspicuous scarlet which it has grown so attached to over the years. So the problem lies fair and square with the PDS.
'Finding an appropriate colour is a great task,' says Mr Spenneberg. 'Whoever succeeds could go down in German history.' At Der Spiegel, Mr Sporl sees things differently. 'We give up. Our only hope is that the PDS will be dissolved, and that we will be left with the old parties. Then our problem will be solved.'