At sixes and sevens
Origin and early history
The phrase probably derives from a complicated dice game called "hazard." It is thought that the expression was originally "to set on cinq and six" (from the French numerals for five and six). These were considered to be the riskiest numbers to shoot for (to "set on"), and those who tried for them were considered careless or confused.
A similar phrase, "to set the world on six and seven", is used by Geoffrey Chaucer in his Troilus and Criseyde. It dates from the mid-1380s and seems from its context to mean "to hazard the world" or "to risk one's life." William Shakespeare uses a similar phrase in Richard II, "But time will not permit: all is uneven, And every thing is left at six and seven."
It is possible that an ancient dispute between the Merchant Taylors' and Skinners' Livery Companies may have helped to popularise the phrase. The two trade associations, founded in the same year, argued over sixth place in the order of precedence. In 1484, after more than a century of bickering, the Lord Mayor of London Sir Robert Billesden decided that at the feast of Corpus Christi, the companies would swap between sixth and seventh place and feast in each others' halls. Nowadays, they alternate in precedence on an annual basis.
The phrase took on additional meaning during the early nineteen-sixties, when debate over Britain's position in Europe under Harold Macmillan centred on membership of the EEC 'Six' or 'Seven' smaller independent states.
The phrase bears comparison with the Chinese phrase luan qi ba zao (亂七八糟), which has a similar meaning but instead uses the numbers seven and eight. Also, it can be compared with the Chilean phrase al tres y al cuatro, with a similar meaning, but using the numbers three and four.