Myanmar's government is pulling out all the stops for a Nationwide Ceasefire Agreement (NCA) that will be signed in front of an international crowd of diplomats, observers and media in Naypyitaw on Thursday.
But only eight out of 16 armed ethnic groups and alliances it negotiated with are signing. Big armed ethnic groups like the Kachin Independence Army (KIA), the Shan State Army (North), the United Wa State Army (UWSA) and the Kokang - with whom the Myanmar army is at war - will not take part.
The agreement has been dismissed by numerous critics as half-baked. But President Thein Sein has staked a lot on the outcome of the tortuous negotiations, seeing it as his legacy to end decades of civil war - at least on paper. The agreement, and the door, remained open for those who wanted to sign later, he told the nation in his most recent radio address.
Analysts taking the long view say there is little alternative to continuing the process aimed at ending sporadic civil wars that erupted soon after Myanmar's independence from Britain in 1948.
The attempt to hammer out a ceasefire, followed by a long-awaited political dialogue as the ethnic minority organisations push back against the Bamar or Burman elites and fight for control of their natural resources, is only the first step.
"They have to push ahead," said Dr Richard Horsey, an independent analyst based in Yangon who has written that the current peace process is a historic opportunity. "There is enormous pressure on him (the President), some of it self-imposed. He has to get something for his efforts."
The groups signing the agreement are not minor. They include the Karen National Union (KNU), the Shan State Army (South), and the All Burma Students Democratic Front (ABSDF). While the ABSDF has negligible forces, it is ideologically important, comprising former students who resisted the erstwhile military regime.
Geographically, it is largely groups on the Myanmar-Thai border that will sign on Thursday, while those on the Myanmar-China border are holding off.
A key negotiator for the government side, Mr Min Zaw Oo of the Myanmar Peace Centre, was quoted by Reuters as blaming China for scuttling the agreement with groups on its border, saying Beijing had discouraged the KIA and the UWSA, and opposed Western and Japanese observers in an area it has long seen as its own backyard.
But yesterday in an interview with the official Chinese news agency Xinhua, Mr Min Zaw Oo said his remarks had been misinterpreted and he had not meant to accuse Beijing of interference.
Another factor holding back some groups from signing up is that they see the current Myanmar government - run by former generals, and with the military controlling key elements of the administration - as an extension of the previous military regime.
"There is a lot of distrust and also, with the Nov 8 General Election coming up, they question why they should sign and give this government political credit," Mr Min Zaw Oo said in a telephone interview from Yangon.
Still, the signing on Oct 15 will demonstrate a degree of trust that has been built through the negotiations. But more important may be what follows - implementation.
Post-Oct 15, this will be largely up to two mechanisms. One is a joint ceasefire monitoring committee, part of whose objective is to protect civilians who for years have been caught up in the sporadic fighting. A Union Peace Dialogue Joint Committee will also be set up within 15 days to start a political dialogue that may be even more contentious in some ways than the ceasefire negotiations.
"The government decided to move forward (and sign the agreement) because it is critical to have a process agreed to by all parties, even if it is not necessarily signed by everyone," Mr Min Zaw Oo explained. "What they (the groups who are signing) want is progressive realisation... The NCA lays out the future of the process, and mechanisms agreed by all the parties, including those that are not signing. It will create the political dialogue."
Potential spoilers include skirmishes between the military and armed ethnic groups, including some of the signatories, and infighting within the groups themselves. Some factions in the KNU, for instance, disagree with the decision to sign the NCA.
"One needs to be sceptical," Dr Horsey said of the agreement. "But I wouldn't be overly sceptical. The text of the agreement was accepted by everybody even if they did not all sign - which means there is no going back to the drawing board."
This makes the delivery of a peace dividend even more crucial, he said. "If in the next six months, the agreement brings political and security benefits, then it will be seen... as a success."