Rugby union numbering schemes

Modern rugby union numbering schemes normally now have the starting players numbered from 1 to 15, and the replacements numbered 16 onwards. But rugby union players have not always been identified by individual labels, nor have the systems used always been the same.

The first use of numbered shirts was the match between New Zealand and Queensland at Brisbane, Queensland in 1897 to allow the spectators to identify the players. In that match New Zealand wore the numbers 1 to 15 starting at fullback, while the hosts wore the numbers 16 to 30.

The practice was adopted for various major internationals but no definitive system was adopted. The matter was brought before the IRB by the English and Welsh Rugby Unions in 1921 but it was decided that the identification of players by marking their shirts was a matter to be determined by the team themselves. Most teams used numbers but in the 1930s, the Welsh used letters. In the early days, a "back-row" was truly a back row, with all three of these player packing down with their shoulders driving the second-row (rather than with the flankers driving the props directly as is required today). Therefore, in many numbering systems these three players were numbered to reflect that (rather than with the two flankers having consecutive numbers as it is today).

Scotland first adopted a numbering system in 1928 for the match against France, but dropped it again immediately. Thus when Scotland played England that year, King George V who attended the game asked why the Scottish players were not numbered, the former president of the Scottish Football Union (as it was then) James Aikman Smith answered This sir is a rugby match not a cattle sale.

...
Wikipedia