Double Repeat Backgammon
What Is It?
This is a backgammon variant I thought up a couple of years ago and I've been
too lazy to implement it until now. But finally here it is!
The basic idea is that after a Double-Take sequence, instead of playing
the game out for double points, you play the game out two times, each time
for single points. You could do this in real life as well; take a quick
photo of the board situation or use a piece of paper to note down the
position. But here at DailyGammon, the computer does the hard work for you.
After a Double-Take, you will see a "Pending Replay" link on the move page,
which shows you what position(s) you have to look forward to when this
current game ends.
An interesting feature of Double Repeat Backgammon is that we can ditch the
Crawford rule. And I will leave you to work out the maths for yourselves,
but it turns out that both players can effectively use the doubling
cube.
Why Is It Interesting?
The two most interesting features of Double Repeat Backgammon are:
- It reduces variance, allowing shorter matches to distinguish who played
better
- It increases the number of doubling decisions
The second point I alluded to above when I noticed the Crawford Rule goes away.
But consider your average 3 point match. In regular, you Double, win a gammon,
and that's that. In double-repeat, you Double, win a gammon, and the match
continues. Or if you Double and get Redoubled, well, that's the match on
this game. In double-repeat, not only is only 1 point (2 on a gammon)
immediately at stake, you can Re-redouble if the odds turn your way. And then
you can get re-re-redoubled.
In fact, the only situation where the Doubling Cube is truly dead is at
double-match-point, when both players need exactly 1 point to win.
How To Try It Out
At some point I plan to add tournaments, but first I want to spend a month
just testing it out. But you can invite your favorite opponent to a match
from the Game Lounge. And, of course, there will
inevitably be bugs, so please send email (not an internal message, if
possible) to Jordan.