Iranian elections aren't easy to read. They're not easy to win either, but more on that later.
Four years ago, I got an extraordinary insight into Iran's politics and its evolving revolution. An election that was thought to be a close run thing between the sitting President Mahmoud Ahmadinejad and his reformist challenger Mir Hossein Mousavi turned out to be anything but.
Ahmadinejad won a landslide, protesters declared the election had been fixed and took to the streets for a week of often violent protests. Covering the election, I was baton-charged by riot police and detained by secret police; a light brush with an authority that cracked down with deadly force to strangle the "Green Revolution" at birth.
They were extraordinary days, with a million people marching in streets saturated with police and very nervous authorities. Some of those I talked to are still in jail. One presidential candidate I interviewed is still under arrest.
Four years on, there is another election but little appetite for revolution or protest. Anxious authorities clearly had no wish to see lightning strike twice, so I didn't get a visa to go back to Tehran.
But in a rare glimpse inside Iran's election campaign, I've spoken to the man who hopes to engineer the biggest change in the country's relations with the West for decades.
In his only interview with a British journalist, Mohammed Reza Nematzadeh spoke to me on a weak but, like his candidate, surprisingly enduring line from Tehran.
He runs the campaign for the reformist candidate who hopes to turn Iranian politics upside down. In the absence of a street revolution, it would be the nearest thing to it.
His man is Hassan Rouhani. He is the only cleric running for president and, ironically in a land run by ayatollahs, he is the sole voice of moderation in a candidate list that could have been drawn up by the Revolutionary Guard and the country's clerical dictators.
It is not just his fluency in English and half a dozen other languages that hints at a different view of the outside world from the current leader.
It is what his campaign manager told me during a Skype interview from his busy headquarters on the final day of campaigning: "We have momentum", Mr Nematzadeh told me. "We are polling better every day and we believe we can do it".
As for vote rigging against his man, he said: "We are optimistic it won't happen. Maybe there'll be small instances in some places, yes. But we believe 90 percent, it will be OK.
"There are observers from all the candidates [at polling stations]. Some interference in our campaign is happening but it it is much improved over 2009 and since the past".
Asked if the Supreme Leader Ayatollah Khamenei would simply not allow a moderate to become president he said "this idea is not correct. Rouhani will work within the law".
But the key point is that he is promising a big change in both the actions and the outlook of the presidency. Mr Rouhani "will be 100 percent different from Ahmadinejad. It is likely that there would be a breakthrough in the nuclear negotiations [with the West]. That is one of the key issues. Though the West, the United States must try more as well.
"Mr Rouhani is a good negotiator," he insisted. "The other and the first key issue is the economy and Mr Rouhani will be different, on the economy, on the president's attitude towards intellectuals and towards the West."
Big promises. First he has to win. And his chances are slim; slim even of getting through the first round of voting and into a run off.
He may be right, however, about a campaign on a roll. There is evidence of a momentum building for Rouhani, who has performed well in the country's television debates. In Iran's version of opinion polls, he is now leading.
ITV News has also recorded an interview with a Tehran activist who worked for another former presidential candidate, Mehdi Karroubi, and was locked up in Evin Prison after 2009.
Esfandiar (he didn't want us to use his full name) says the mood had changed completely since another moderate candidate withdrew from the race this week and Rouhani took the lead in the polls for the first time.
He and his fellow reformists are now determined to vote and, he claims, they have an energy reminiscent of 2009. “Many people who didn’t want to take part in the election have changed their minds. Nobody can be sure it won’t be rigged but it’s the only way we have," he said.
"Rouhani is not our first choice. He’s not who we really want but he’s better than the others. He’s not a conservative. He’s not supported by the Supreme Leader. He’s not a crazy guy without a brain like Ahmadinejad. We don’t have anything more than hope”.
A faint hope it may be. But it is a hope they will cling to, as more than 40 million Iranians go to the polls on Friday.