Variations

 Cancelgammon

 From: Ilia Guzei Address: iguzei@chem.wisc.edu Date: 31 March 2004 Subject: Cancelgammon strategy Forum: GammOnLine

```Last night our club ran an experimental tournament of cancelgammon. The
starting position was as in Diagram 1 and during each game each opponent
could cancel one opponent's roll. When a roll is cancelled the person
whose roll was cancelled rerolls. Cube actions cannot be cancelled.

In general I found this game more mentally demanding than normal BG - more

24  23  22  21  20  19      18  17  16  15  14  13
+---+---+---+---+---+---+---+---+---+---+---+---+---+
| X   X               O |   |     O               X |
|     X               O |   |     O               X |
|                     O |   |     O               X |
|                     O |   |                     X |
|                       |   |                     X |
|                       |   |                       |
|                       |   |                       |
|                       |   |                     O |
|                     X |   |                     O |
|                     X |   |     X               O |
|     O               X |   |     X               O |
| O   O               X |   |     X               O |
+---+---+---+---+---+---+---+---+---+---+---+---+---+
1   2   3   4   5   6       7   8   9  10  11  12

During one of my matches I was X in the position below. No roll has been
cancelled in this particular game. Question: Should I double? If I double
and hit, my roll will be cancelled and I would have to try to hit with the
cube on 2. If I do not double and hit my roll will be cancelled as well
and then I can double. Thus in both situations I would have to hit with
the cube on 2. But! If I do not double, hit and have the roll cancelled,
do I have the right to double before rerolling? In normal BG if one takes
a shake and his dice pop out cocked s/he must reroll, but s/he cannot
double instead of rerolling. Does the "cancel" part of cancelgammon
require a modification to this rule?

Match to 5, tied at 0
X on roll. Cube Action?

24  23  22  21  20  19      18  17  16  15  14  13
+---+---+---+---+---+---+---+---+---+---+---+---+---+
|     O   O       O   O |   |     O               X |
|     O   O       O   O |   |                     X |
|     O   O       O   O |   |                       |
|     O                 |   |                       |
|                       |   |                       |
|                       |   |                       |
|                       |   |                       |
|                       |   |                       |
|                       |   |                       |
|         X       X   X |   |                       |
| X   X   X       X   X |   |                       |
| X   X   X       X   X |   | O                     |
+---+---+---+---+---+---+---+---+---+---+---+---+---+
1   2   3   4   5   6       7   8   9  10  11  12

Ilia
```

 Gary O  writes: ```Interesting variant! I would allow cube action after a cancel (SLIGHT amount of vig to the person with a cancel left) I think the double, roll, cancel should include notching the cube back (still allowing another cube action on that turn - increases intropy for the uninitiated.) the cancel option looks to have implications for checker play. (ie. you hit he canceled, how would you play a 63 with or without your cancel option --- if you still had cancel 13/7*, 13/10 but without the option you might rather play 13/7*, 6/3 halving the chance of the fly shot. This position looks like double/take. Perhaps another rule change would allow each player to cancel one of their own rolls (I've had WAY to many rolls that I'd like to reroll) ```

 Happy Juggler  writes: ```What would normally be a cube in volatile positions will usually not be a cube if your opponent has not used his cancel yet. In this position I would not cube here with those rules. If I do not roll well the roll will stand. If I do roll well the roll gets canceled. Therefore the bad rolls for X will come up more often. I would roll here. If I rolled poorly I would be glad I did not cube. If I rolled well then white would cancel, and then I would cube. ```

 Tom Ewall  writes: ```I think it makes more sense to allow doubling after a cancel than to proscribe it. I think this position is a double even with the cancel. It's true you lose some of your equity because your opponent's cancel, but you also have a cancel available, which mitigates that somewhat. ```

### Variations

Acey-deucy  (J. Nagel, Dec 2004)
Acey-deucy  (Steve Ewert, June 1998)
Acey-deucy  (Lee+, Jan 1997)
Acey-deucy  (John David Galt+, Dec 1995)
Acey-deucy  (James Eibisch, Apr 1995)
Backwards play  (Colin Bell+, Feb 1996)
Best-of-n variant of match play  (Tim Chow+, Feb 2009)
Bluff Cube  (Timothy Chow+, Dec 2012)
BluffGammon  (Christian Munk-Christensen, June 2009)
Cancelgammon  (Ilia Guzei+, Mar 2004)
Domino backgammon  (Laury Chizlett, Sept 1999)
Duodecagammon  (David Moeser, Dec 2000)
Duplicate backgammon  (Dean Gay+, Jan 1997)
Duplicate backgammon  (Albert Steg, Feb 1996)
Exact bearoff  (Chris Moellering+, Dec 2002)
Fevga  (George, Sept 2004)
Fevga (or Moultezim)  (Igor Sheyn+, May 1995)
Freeze-out match  (Dave Brotherton, July 1998)
Gabgammon  (jckz, Oct 2005)
Greek backgammon  (Alexandre Charitopoulos, Aug 2003)
Greek backgammon  (Alexandros Chatzipetros, June 1997)
Greek backgammon  (Marc Jacobs+, Feb 1994)
Hit man  (Matt Reklaitis, Jan 2004)
Hyper backgammon  (Gregg Cattanach+, Dec 2000)
Hyper backgammon  (Michael A Urban, Oct 1993)
International backgammon  (Bob Lancaster+, Oct 2002)
Jacquet  (Mark Driver, June 2001)
Joker cube  (Joe Russell+, May 2011)
Khachapuri  (Michael Petch+, Sept 2010)
Kleinman's tandem backgammon  (Fabrice Liardet+, May 2010)
LongRun  (Bill Hickey, Mar 2010)
Longgammon  (Michael Strato, Dec 2000)
Low number first, fixed dice, others.  (Walter Trice, Jan 1997)
Mexican  (Tom Henry, Apr 1997)
Middle Eastern backgammon  (Alan Cairns, Mar 2002)
Misere (backgammon to lose)  (Jason Lee+, July 2004)
Misere (backgammon to lose)  (Jason Lee+, Apr 1995)
Misere, Chase, Skewed dice  (Stein Kulseth, Jan 1997)
Nackgammon  (Ken Arnold, July 1996)
Nackgammon Shuffle  (Stick, Sept 2011)
Nackgammon opening moves  (Warwick+, Feb 2002)
Narde  (narde, Nov 2006)
Nardi  (KL Gerber+, Nov 2002)
No hit  (RedTop+, May 2004)
Nuclear backgammon  (Walt Swan, Apr 1997)
Old English  (Nick Wedd+, Feb 1996)
One roll lookahead  (Stephen Turner, Mar 1997)
Opening slot rule  (Gregg Cattanach, June 2006)
Other variations  (Douglas Zare, Feb 2000)
Plakoto  (Ed Dengler+, May 1995)
Plakoto  (Pasteel M., Feb 1994)
Plakoto express  (Athansios Vagias, Feb 2005)
Portes  (George, Sept 2004)
Roll-over  (Edward D. Collins, Oct 1997)
Russian backgammon  (Daavid Turnbull, Aug 1991)
SassanGammon  (Chiva Tafazzoli+, June 2009)
Shesh Besh  (G.S., May 2003)
Simborg Rule  (Scott+, Feb 2005)
Slot backgammon  (Fabrice Liardet+, Aug 2008)
Sudden death, Woodpecker, Gerhardsen  (Fredrik Dahl, Jan 1997)
Tablestakes betting  (TrueMoneygames, June 2002)
Takhteh  (Bruce Scott+, Mar 2003)
Tandem Backgammon  (Mislav Kovacic, Feb 2012)
Tavla  (Arda Findikoglu, Nov 2004)
Tavla  (ucc02cx+, Feb 1997)
Tavli (Portes, Plakoto, and Fevga)  (Jens Larsen, July 1997)
Tavli question  (Brus+, Apr 2011)
Tracy turn around  (Michael J. Zehr, Feb 1996)
Tri-gammon  (Gregg Cattanach, Sept 2000)
Trictrac  (David Levy+, May 1998)
Trigammon  (James Eibisch, Jan 1997)