Yan Tan Tethera

In order to keep accurate records (e.g. of birth and death) and to be alert to instances of straying, shepherds must perform frequent head-counts of their flocks. Dating back at least to the medieval period, and continuing to the present in some areas like Slaidburn, farms were granted fell rights, allowing them access to common grazing land. To prevent overgrazing, it was vitally important for each farm to keep accurate, updated head-counts.

Though fell rights are largely obsolete in modern agriculture except in upland areas, farms are often subsidised and taxed according to the quantity of their sheep. For this reason, accurate counts are still necessary, and must be performed frequently.

Generally, a count is the first action performed in the morning and the last action performed at night. A count is made after moving the sheep from one pasture to another, and after any operation involving the sheep, such as shearing, tagging, foot-trimming, mulesing, etc., although sheep are far less likely to stray while being moved in a group than when grazing at large on open ground.

Sheep-counting systems ultimately derive from Brythonic Celtic languages, such as Cumbric; Tim Gay writes: “[Sheep-counting systems from all over the British Isles] all compared very closely to 18th-century Cornish and modern Welsh".[5] It is impossible, given the corrupted form in which they have survived, to be sure of their exact origin. The counting systems have changed considerably over time. A particularly common tendency is for certain pairs of adjacent numbers to come to resemble each other by rhyme (notably the words for 1 and 2, 3 and 4, 6 and 7, or 8 and 9). Still, multiples of five tend to be fairly conservative; compare bumfit with Welsh pymtheg, in contrast with standard English fifteen.

Like most Celtic numbering systems, they tend to be vigesimal (based on the number twenty), but they usually lack words to describe quantities larger than twenty; though this is not a limitation of either modernised decimal Celtic counting systems or the older ones. To count a large number of sheep, a shepherd would repeatedly count to twenty, placing a mark on the ground, or move his hand to another mark on his crook, or drop a pebble into his pocket to represent each score (e.g. 5 score sheep = 100 sheep).

Their use is also attested in a knitting song from Yorkshire.[6] Similar modern references have since been made in both products produced and sold within Northern England, such as prints,[7] beers,[8] and yarns,[9] as well as artistic works simply referencing the region, such as Sir Harrison Birtwistle's 1986 opera Yan Tan Tethera.

• Counting-out game

• Rawnsley, Hardwicke Drummmond (1987) "Yan tyan tethera: counting sheep". Woolley: Fleece Press ISBN 0948375175

• Cornish numerals, including mp3s for pronunciations
• Breton numerals
• Carol Justus's use of this numbering system to explain pre-decimal counting systems
• The Sheep Counting Score – By Walter Skeat, 1910
• Modern Welsh decimal system and older vigesimal system in full