House rules: the backgammon variations families swear by

Ask ten people how backgammon works and nine will agree.

The tenth will tell you that in their family, doubles let you roll again, and they'll say it with the confidence of someone quoting scripture.

Backgammon has an official rulebook. It also has thousands of kitchen-table versions, passed down by people who learned from an uncle who may have been making it up.

The ones you'll actually run into

Doubles roll again. Roll double fours, play your four moves, then roll again. This is a real rule in some related games, so whoever taught it to your family wasn't inventing it. Just know that it isn't part of standard backgammon.

No hitting on the first roll. A grace period, usually justified as "it's not sporting". Not standard, but harmless.

You must bear off exactly. No using a 6 to clear your 4-point; you wait for the right number. It makes the ending much slower and feels more dramatic.

The loser sets up the board. Not a rule at all, but enforced more strictly than most.

Playing to five points rather than one game. Points, not games: a single win scores one, a gammon two, a backgammon three, so a five-point match can be over in two games or run to nine. Perfectly standard, and the usual way matches work.

The ones that are real, even though they sound invented

These four turn up at kitchen tables and sound like somebody's invention. All four are in the book as optional rules, and all four involve the doubling cube: the block that says what the game is currently worth. Offer it, and your opponent either accepts and plays on for double, or gives up the game there and then.

Automatic doubles: you each roll one die to see who starts, and you both roll the same number. Instead of simply rolling again, the game is now worth double before anyone has moved a checker. Common in friendly games, not used in tournaments.

Beavers: your opponent doubles, you think they have misjudged the position, so you accept and immediately double again. The cube stays on your side of the table, so they cannot double you back. Friendly money games only, and pleasingly cheeky.

The Jacoby rule: a gammon or a backgammon only counts double or triple if somebody has used the cube in that game. Otherwise a thrashing is worth the same as a narrow win. It exists to stop hopeless games being played out for the extra point. Widely used in money games, never in matches.

The Crawford rule: in a match, once one player is a single point from winning, the cube is put away for the next game only. Without it, whoever is behind could double every game with nothing left to lose. Standard in tournaments.

Why families end up with their own rules

Backgammon is taught by people, not by books. Someone learns it in a cafe on vacation or from a set in the back of a cupboard, remembers nine rules out of ten, invents the tenth, and teaches it to their children as fact.

It's been happening for centuries, which is also how the game ended up with so many national versions: Tavla, Tavli, Nard, all cousins with their own rules about hitting and blocking.

What to do when the rules differ

Agree before the first roll. It takes ten seconds and saves an argument in the bear-off, when one of you will be very motivated to remember things differently.

And if someone's family rule is clearly nonsense: play it their way once. It's their table, and you'll probably learn something.

The short version

• "Doubles roll again" is common, but not standard backgammon.
• Bearing off exactly, no hitting on the first roll and "the loser tidies up" are house inventions.
• House rules exist because the game is taught by people, not books.
• Agree which rules you're using before the first roll.
• Automatic doubles, beavers, the Jacoby rule and the Crawford rule are all real, and all optional.