BERLIN — A game is not just a game when it pits the national soccer teams of the deeply intertwined countries of Germany and Turkey against each other.

When the German team takes the field Wednesday night against Turkey in Basel, Switzerland, in the semifinals of the European Championship, it will also face two German natives on the Turkish side. The versatile midfielder Hamit Altintop hails from the West German city of Gelsenkirchen and defender Hakan Balta is a Berliner.

The World Cup gives national teams the ultimate soccer bragging rights, but the neighborly rivalries in the European event make for what at times feels like a more intense tournament. The frenzy is reaching a peak over Wednesday’s intriguing semifinal because of the estimated 2.7 million people either of Turkish citizenship or heritage living in Germany, the country’s largest minority.

With both teams still alive, it has been doubly festive here and up to this point mutually supportive, as many Germans have cheered on the Turks and vice versa. Each Turkish victory in the tournament has brought enthusiastic fans draped in the country’s red flag onto the streets, where they set off firecrackers and shot bottle rockets into the night sky, with parties often lasting until morning. German fans have packed pubs and beer gardens for their team’s run to the semifinals.

Now the country is practically humming with anticipation for the match, with an overriding optimism for a nationwide party spiked with an edge of nervousness that a friendly sporting rivalry could spill over into something more serious in the streets. Police officials say they are prepared, especially in Berlin where some 500,000 people are expected at the public viewing area at the Brandenburg Gate.

All of Europe has been in the grip of what it calls football fever for the past two and a half weeks as the Continent’s best teams have squared off. The tournament has given audiences some displays of masterful soccer, but also more than a few intriguing subplots as the increasingly mobile populations around Europe and the world create an overlapping web of confused loyalties.

Mixed allegiances are hardly new to international soccer. Players often duel against teammates and friends from their professionals squads. Some coaches know no borders. Russia’s coach, Guus Hiddink, celebrated his team’s latest victory over his home country, the Netherlands.

And, as in the Germany-Turkey matchup, there are often political overtones. A matchup in the final between Germany and Russia, which plays Spain in the other semifinal, could well exhaust a decade’s worth of World War II references.

The Germans already faced Robert and Niko Kovac, brothers born in West Berlin, when they lost to Croatia in the group round. Not that German soccer fans are in any position to complain about the Croats or the Turks, seeing how their team beat neighboring Poland, 2-0, in its tournament opener with both goals from Lukas Podolski, one of the squad’s three Polish natives.

Though Austria and Switzerland have been the co-hosts of the European event, the ouster of both countries’ teams in the group stage meant that they were not the stars of their own show. If the most memorable symbol of Germany’s successful hosting of the World Cup in 2006 was the German flag displayed without shame or second-guessing, the motif this time around for German spectators are the twin Turkish and German flags flapping from countless car windows around the country.

“Of course my heart lies first with the German team,” said Rainer Krause, 63, a Berlin native who bought a red Turkish flag as well as a German one at a store in the heavily Turkish Neukölln neighborhood, where he works., “But over the decades the loyalties have grown together, there are such strong feelings of connection.”

Altintop, who plays for the German club champion, Bayern Munich, agrees. In an interview this week with Spiegel Online, he declared, “I owe much, actually everything, to Germany.” But when asked whether he considered himself German at heart, Altintop, the Turkish team’s mainstay, reinforced the sense of dual loyalty, saying: “No. Maybe I’m both.”

.............HEP SENİNLEYİZ TÜRKİYE....................

........TURKEY WİLL THİS MATCH...................

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....WE MUST FİNİSH.....