"It's still very popular. You might think that people would've forgotten it, but that's not the case at all."

Peter Hoffmann is a spokesman for the Haus der Geschichte in Bonn, a museum covering the history of the Federal Republic of Germany since 1945. Every year, thousands of people flock there to see remnants of the Berlin Wall or the luxurious Mercedes Benz W186 used by former Chancellor Konrad Adenauer. However, the aforementioned visitor attraction whose enduring appeal Hoffmann told FIFA.com about is a mere piece of paper, albeit the most famous one in FIFA World Cup™ history: Jens Lehmann's 'cheat sheet'.

"Lehmann's list". These words are enough to take any football fan straight back to the Olympiastadion in Berlin on 30 June 2006. It was Germany against Argentina in the quarter-finals, in an emotionally charged match that ended all square after 120 minutes. The atmosphere had been funeral-esque when Roberto Ayala gave the Argentinians the lead with a towering header, only for Miroslav Klose to set the place rocking again by heading home an equaliser with ten minutes to go.

And so it was that the ordeal of penalties was required. The notes that Lehmann consulted before every La Albiceleste spot-kick he faced would become synonymous with the hosts' eventual 4-2 triumph, which led the buzz among the German people to hit fever pitch and emboldened them to openly express their patriotism after decades of keeping such sentiments under wraps.

"For us it symbolises how the country and particularly young people celebrated on the streets during the World Cup, waving their flags amid an atmosphere of football-mad excitement," Hoffmann said. This 'cheat sheet' gained heroic status: retrieved by Bild newspaper, it was auctioned off on famous charity television programme Ein Herz für Kinder (A Heart for Children) and bought for €1 million by Utz Claassen, the CEO of Germany energy giant EnBW. In 2007 the businessman donated it to the museum, where it is showcased in a display unit in the information centre.

"Everything went the way we expected. We left nothing to chance," said a thrilled Andreas Kopke, the Die Mannschaft goalkeeping coach, after the game. It was he who, together with Dutch coach Huub Stevens, had sifted through a database of 13,000 previous penalty kicks to compile a series of tips for Lehmann, which became the now-iconic scrap of notebook paper bearing the letterhead of the Schlosshotel in Berlin.

Juan Roman Riquelme, who did not feature in the shoot-out because he had been substituted in the 72nd minute, later sought to debunk what he felt was a myth surrounding Lehmann's crib sheet. "There wasn't anything written on that piece of paper," he told FIFA.com. "There wasn't anything on it. It was all about delaying the kicks that bit longer and making our penalty-takers think he knew where they were going to shoot. He was very sharp in the way he tried to put our players off."

Lehmann denied this claim: "I wrote down the names of the Argentinian players that same day, in the morning. We were playing in the afternoon and I noted them down in the morning." He did, however, accept that the notes were "pretty illegible". Klose, for his part, said that he never saw what was on the slip of paper – he has not been to the museum to check it out – but was adamant that its role was in keeping with Lehmann's meticulous approach: "It was typical of Jens to watch videos of penalties to analyse how the takers positioned their feet when they struck the ball and where they would put their kicks in important matches."

To thicken the plot, of the seven players whose names had been scribbled in pencil – Riquelme, Hernan Crespo, Gabriel Heinze, Ayala, Pablo Aimar and Maxi Rodriguez – only two actually took kicks. Jens did exactly what his notes told him to and saved Ayala's effort. He went the right way for Rodriguez's too, but it was so well hit that it found the net anyway.

Argentina's fourth penalty is where the two conflicting versions of events converge. Esteban Cambiasso stepped up with his side trailing 4-2 and knowing that he had to score to prevent Germany going through to the semi-finals. Cambiasso was not on Lehmann's list, yet the keeper did have an inkling based on his video research: "He'd played for Inter against Villarreal in the Champions League. I didn't know how he took penalties, but by watching that match I got an idea of the corners and sides Cambiasso was most comfortable with."

In the view of German film director Sonke Wortmann, there is at least some substance to Riquelme's theory about Lehmann psyching out the Argentina players. During the tournament, Wortmann was making Germany: A Summer Fairy Tale, a documentary based on Jurgen Klinsmann's team's exploits, and so he witnessed the keeper's actions in the flesh: "Lehmann couldn't find anything in his notes indicating where Cambiasso might put his kick. However, the piece of paper played a part because Lehmann took his time and then stared at him, nodding his head as if he knew what to do."

Leading up to that game, Germany had been struggling against fellow world football powerhouses, losing ten such games since 2000 and drawing another six. Perhaps this is what prompted Oliver Kahn's pre-match remark that, "We have a very favourable track record in shoot-outs. We can go through without winning."

Either way, Lehmann's preparation and mind games bore fruit and he kept out Cambiasso's strike. In the aftermath, Germany were able to celebrate being Germany in a way they had not been able to for some 60 years. All of this is reason enough to make it "highly interesting", in Hoffmann's words, for "a museum that is not about football but about the history of the Federal Republic of Germany" to exhibit what might seem to be nothing more than a simple piece of paper.