He was just always aware of it, he says. “I played it as a child in the 1950s. I must have played it at primary school.” He wonders if it’s coincidence—and thinks it probably is—that the person from whom he remembers learning Bulls and Cows was the child of a dairy farmer.

Is it possible that Mastermind evolved from some kind of traditional farm game? Siobhán Gleeson, who grew up on a farm in County Cork, Ireland, doesn’t really think so, but offered a theory to explain the name why Bulls and Cows was ever an appropriate name for a game of numbers and taxonomies. “Maybe it had something to do with cattle tags? Like the ones that are on their ears? I keep one of our old ones in my jacket pocket as a reminder of my [late] dad which is why it came to mind. Maybe when this game came about only bulls had ear tags with numbers?” Gleeson brought up the puzzle to her sister Marie. Marie recognized the puzzle but didn’t know it had a name, and couldn’t remember exactly how she learned of it.