The Stasi are, of course, long gone; only their taste in interior decoration remains. This month, it was the Party of Democratic Socialism that chose to rent the hunting lodge for two days - a curious closing of the circle. The PDS is the successor to the East German Communist Party, which created and nourished the Stasi. One of the main tasks of the PDS is to break free from the Stasi legacy with which it is still saddled today.
The strategy meeting, just outside the village of Treppeln, was attended by the PDS leadership from the east German region of Brandenburg, including Lothar Bisky, the party's national leader since last year. Planning sessions were held on everything from sport to the economy. The party was in cheerful mood. In elections in Brandenburg last month, the former Communists pushed Helmut Kohl's Christian Democrats into third place. The former Communists are no longer taboo.
The party's 'Janus quality', as it has been called, is, however, a serious problem. On the one hand there are those who are strongly represented at the Treppeln session - former reform-minded party members, or those who were kicked out of the party. On the other, there are the old-timers, who joined the post-unity PDS as the next-best thing to the old Communist Party and who still seem locked into the past.
The strength of the old-timers alienates the new voters whom Mr Bisky needs; and yet, if he cracks down too hard on those who pine for the old East Germany he will lose a substantial section of his membership. Mr Bisky sidesteps this contradiction by suggesting that he respects the old- timers' 'ability to learn'.
Political opponents dub the PDS the Partei der Stacheldraht - the Barbed-Wire Party. More accurate may be the party's own description of itself, as the 'party of losers', following German unity. Above all, Mr Bisky emphasises the party's eastern identity when he explains his loyalty to the re- invented Communist Party. 'I reject colonialisation and the creation of second-class citizens. We can't make a policy of nostalgia. But we profit from the fact that we are from the east - and people trust us for that.'
Elsewhere in Eastern Europe, economic difficulties have been the most important reason why ex-Communist parties have gained support. In east Germany, however, questions of identity have been as important as economic loss.
Mr Bisky acknowledges that it will be difficult for the PDS to break through the nationwide 5 per cent barrier to gain seats in the German parliament in elections in the autumn. He seems little interested in building up a western party and is almost openly dismissive of west German left- wingers who have joined the PDS. Instead, he hopes for direct mandates in the east - which, under the German voting system, would entitle the party to further seats.
Few in the east believe, however, that the former Communists can ever again dominate. Their strength is, above all, as an opposition party against the big-party consensus and as a campaigning party on local issues. On the streets of Potsdam few condemn the PDS outright. Marianna Otto, a research worker, says she would never vote for the PDS because the Communist legacy is too strong. But she is bemused by the vehemence of the western reaction. 'I can understand very well why people should vote like this. The West created so many illusions, which were not true.' Eberhard Wassel, a bus driver, says: 'It's good news, that there's an opposition against the big parties. That's in the interests of east Germany.'
Despite the economic difficulties faced by east Germany today, Mr Bisky freely admits: 'Everybody is better off (than in 1989) - that's clear.' Instead, he argues: 'We all speak German - but we don't understand each other.' Does that mean that, when Germany finally becomes one country - however many years that may take - there will no longer be a role for his party? 'Perhaps.'Reuse content