Doha rejects Tehran's claim about three pilots, and both sides now dispute the existence of the room.
Qatar denies holding three Iranian pilots, and Iran says it has the paperwork. The row has now moved on from the men to whether the building holding them exists. Three countries have offered a neutral room, which is also disputed.
Qatar has denied detaining three Iranian pilots. Iran insists it has the paperwork. The dispute has since moved on from the men entirely.
Both capitals now disagree about whether the building in question exists. This is a novel escalation. It is also, on inspection, the oldest escalation there is.
Doha's line is firm. Nobody is being held. The corridor where nobody is being held is likewise unoccupied.
Tehran's response was to release a floor plan. Doha countered with a floor plan of the same site showing a car park. Neither plan has a north arrow.
"We have offered to give them a tour," said Qatari foreign ministry spokesman Nasser al-Rumaithi. "They declined. They said a tour would legitimise the corridor."
An Iranian official, Reza Kamalvandi, put it differently. "The corridor is a matter of record," he said. "Whether the record is a matter of the corridor is for lawyers."
The mediators arrive
Three separate countries have now offered to mediate. All three have offered to host the talks in a neutral room. The room's status is itself contested.
A Swiss delegate suggested a tent. The tent proposal collapsed over the question of flooring. Everyone involved described progress.
"The gap between the parties is narrow," one mediator said. "It is roughly the width of a wall neither side admits is there."
Regional analysts note the pattern. Denial, counter-denial, competing architecture, then a communique nobody reads. One is reminded, inevitably, of every previous fortnight.
The three pilots, if they exist, have not been heard from. If they do not exist, they have been unusually consistent about it. Both governments cite this silence as support for their position.
Talks are expected to resume on Thursday. The venue has not been agreed. The venue's existence has not been agreed either, which officials say gives them flexibility.
