Three-year residency rule has proved very beneficial to Ireland in recent years. 4 Irish Rugby Players Whose International Careers Somehow of favouring Ireland-based players in team selections, a unwritten rule that has. Rugby union in Ireland is a popular team sport. Rugby union is organised on an all-Ireland The rules also varied according to region, some games being more disciplined than others. The number of players varied from place to place, though National team : Ireland.