The Rare 2d Coil was an experimental vertical coil stamp, denominated 2d, issued by the Irish Post Office in 1935^[2][3] and is one of the scarcest, and most valuable, Irish stamps. It is often referred to by stamp collectors simply as "Scott 68b" or "SG 74b",^[1] being the Scott and Stanley Gibbons stamp catalogue numbers respectively.

Philatelists refer to the configuration as '"perf 15 x imperf",^[4] or in the US as "perf 15 horizontal", because the stamp is perforated 15 gauge (holes per 2 cm) on the horizontal and imperforate on the vertical edges. Because of the shared design it appears identical to the first 2d value definitive stamp issued on 6 December 1922 with the Map of Ireland except for the imperforate vertical edges.^[1] It uses the first Irish watermark that was a stylised design of the two overlapping letters 's' and 'e' making an 'se' watermark representing the name of the country Saorstát Éireann (Irish Free State).^[1][5]

It was first recognised in 1937^[4] but not acknowledged by the philatelic catalogues until the Scott stamp catalogue listed it in 1952. Over the years 20 copies have been identified in mint condition,^[6] but the quantity of used stamps is not known. Even though several have been recorded, they are nevertheless scarce.^[7] A few copies of the stamp are known to exist on cover, but Dulin points out that all Irish coil stamps are scarce on cover.^[8] Some debate as to the genuineness of this stamp took place in the Irish philatelic literature during the mid-1990s with a suggestion the stamp had been fabricated from a normal fully perforated stamp with a press. This hypothesis was debunked by Foley and Ian Whyte, a Dublin stamp dealer, who both claimed such a process would damage the stamp and be scientifically impossible. Archived documents were also found that confirm the stamp was ordered and issued by the Irish postal administration.^[9][10]

• 2d Map of Ireland definitive stamp perforated on all sides from a regular sheet of stamps; 1st letter rate stamp
• Gerard Brady example 1 sold in Dublin in May 2016 for €10,000 by Whyte's^[11]
• Mint 68b that received a Philatelic Foundation Certificate in 2010 was sold in an April 2011 Kelleher auction for $12,500.00 (plus 15% buyer fee)^[12]

A detailed survey of the then twenty known unused examples was carried out by Gerard Brady and published in the Irish Stamp News in 1981.^[13]

In 2004 a forgery of this stamp was reported in The Revealer, the journal of the Éire Philatelic Association, that had been found in the "Maryland forgeries" and offered for sale by a noted collector Roger West of Phoenix International. The forgery is paler than the genuine stamp and the print is coarser, on a white ungummed paper and perforated 10.75 x imperf. The printed stamp area is 18.0mm x 22.5mm compared to 18.5mm x 22.0mm on the original.^[14]

• Postage stamps of Ireland
• Definitive postage stamps of Ireland