In Britain, it's very well known by those of us who are 40+, and I think even younger people will at least have heard of it, even if they haven't played it them

In Britain, it's very well known by those of us who are 40+, and I think even younger people will at least have heard of it, even if they haven't played it themselves. It was an absolute staple of playgrounds in the 1980s. There's a rich history of supposed 'cheats' — boiling the conker in vinegar was a classic. And, note, conker, not chestnut (two different things).