MaBaGa
MaBaGA is a small backgammon club for people who enjoy the game and the company that comes with it. We meet up, roll the dice, lose gracefully (most of the time), and keep score — because someone always wants to know who’s on top.
There’s no test to pass and no rating to live up to: just a board, two players and a bit of luck you have to earn. Beginners are always welcome — the regulars were all beginners once too.
Once a month we get together for Hit the Bar — a relaxed club night at a local café where everyone’s welcome to drop by and play a game or two.
MaBaGA Standings
A live Elo ranking for our backgammon club. Anyone can follow along; admins enter the games and the standings update in real time.
How the Elo system works
Every player starts at 1500. After each game, points shift between the winner and the loser. How many depends on the rating gap and on how decisive the win was.
expected_1 = 1 / (1 + 10^((rating_2 − rating_1) / 400))
shift = K × margin × (result − expected_1)
margin = 1 + 0.5 × ln(points) points = base × cube- K = 32 sets the sensitivity (higher K = bigger swings).
- base: single = 1, gammon = 2, backgammon = 3.
- cube: the value of the doubling cube (1, 2, 4, …) is multiplied in.
- The shift is always symmetric: what the winner gains, the loser loses.
Examples
| Situation | Winner gets |
|---|---|
| Underdog (1500) beats favourite (1700), single | +24 |
| Favourite (1700) beats underdog (1500), single | +8 |
| Equal ratings, single game | +16 |
| Equal ratings, gammon with cube 4 (8 pts) | +33 |
Single
Standard win. Base value 1.
Gammon
The loser hasn't borne off a single checker. Value 2.
Backgammon
The loser still has checkers in the winner's home board. Value 3.