Mastering Backgammon

Playing 2-1 on the Second Roll
by Bill Robertie
This article originally appeared on, May 25, 2007.

Earlier in this series, we looked at the various possibilities on the opening roll. Of the 15 opening rolls, five were virtually forced: 3-1, 4-2, 5-3, 6-1, and 6-5. In these cases, either making a blocking point or running to the midpoint was far better than any other play. Another eight rolls (6-3, 6-3, 5-4, 5-2, 4-3, 3-2, 2-1, and 5-1) were tossups. In each case, there were at least a couple of plays that were extremely close in value. The last two rolls (6-2 and 4-1) had a correct play, but the alternatives were not so bad that they could be considered blunders. Mastering the theory of the opening roll took a little work, but wasn't really an arduous process.

Replying to the opening roll, however, is a different story. Now we're really starting to play backgammon, and the choices become more numerous and more complex. In this column we'll take a look at how Black should play a 2-1 when White has won the opening roll. Since White's 15 possible opening rolls can be played in various ways, (as many as four reasonable ways for rolls like 4-1 and 4-3), I'll present the information first in a tabular form, and then follow with a discussion, grouping common themes together for easier understanding.

In the table, White's possible roll and play is listed first, followed by my recommendation on how best to play a 2-1 in response.

Wow! Quite a list. Now let's try to tease some order out of this chaos. Let's start with the most obvious plays first.

  • If White runs to your 9-point or 10-point with 6-3 or 6-4, hit. If you have a leftover ace, split your back men.

  • If White splits to your bar-point (6-2, 6-3, 6-4, or 5-1), hit with the ace, and play 13/11 with your deuce. Slightly inferior is playing 24/22 with the deuce. Although the split is now perfectly safe, the hit starts a little attack, and 13/11 helps the attack a little more.

  • If White splits to your 5-point (4-3, 4-5, and a couple of oddball 4-1s), hit with the ace, and back up the hit with 13/11. Fighting for the 5-point is absolutely critical in the opening. As before, you want to have as many covers for the blot on the 5-point as possible, so 13/11 is the right deuce.

  • If White splits to your 4-point (4-3 or 3-2), hit again. The 4-point is also crucial, though not as crucial as the 5-point. Now there is no good ace except 24/23.

  • If White splits to both the 5-point and 4-point (with theMiddle Eastern split, 4-3 played 24/20, 24/21), hit them both! An unusual variation.
These plays should all have been pretty clear. Now we move on to a couple of very important, but less well-understood categories.
  • If White makes an inner point (3-1, 4-2, 5-3) you want to build and split with 13/11, 24/23.

  • If White brings down two builders (with 4-3, 3-2, 5-4, 5-3, or 5-2), you do not want to split. Instead, you slot with 13/11, 6/5. The basic idea behind these two groups of rolls is as follows:

If White has lots of attackers (defined as spares in the inner board and all checkers in the outer board), you have less desire to split, because the split checkers are vulnerable to attack. Instead, you want to keep your back checkers together, and instead build and slot on your side of the board.

If White has points but few attackers, you have an increased desire to split, to try and escape or make an anchor before you get boxed in.

In the starting position, White had one inner board point (the 6-point) and six attackers (the three spares on the 6-point plus all three checkers on the 8-point). Once he makes the 5-point with a 3-1, he now has two points, tying up four checkers, and only four attackers (the two spares left on the 6-point plus the two remaining checkers on the 8-point). Compared to the starting position, you (Black) now have a greatly increased desire to split, because White has more inner points and fewer attackers left to harass you. Since 2-1 was pretty much a tossup between splitting and slotting in the starting position, splitting must now be a clear play.

But suppose instead White starts with 4-3 and brings down two checkers, 13/9 and 13/10. Now he has the same number of points, but eight attackers instead of six. Now splitting with 2-1 is much more dangerous, so the slot with 13/11, 6/5 is clear.

Make sure you understand the point of the last few paragraphs; it's a key insight into the play of opening move replies.

  • If White has slotted his 5-point (with 2-1, 4-1, 5-1, or 6-2) then you should slot as well, 13/11 and 6/5. The slot is now less dangerous than on the opening roll because if White hits without covering his 5-point, you have many return shots.

  • If White has split his back men but has not brought a new builder to bear on his 4-point (2-1 played 13/11, 24/23, 5-1 played 13/8, 24/23, or 6-2 played 24/16), split all the way up to the 21-point with 24/21. Playing simply 13/11 is less effective when White has split his back men, and the 21-point is a good anchor to grab if White has not brought pressure on it.

  • If White has made some other splitting play, then play 13/11, 24/23.

  • If White has made some other non-splitting play, move 13/11, 6/5.

The most general rule for all replies to opening rules is a very simple one: Do what your opponent did. If he split, you want to split. If he slotted or brought down builders, you want to slot or bring down builders. Whatever he did on his opening roll is a good clue to what you should do in reply.

Next time:  Playing 2-2 on the Second Roll

See:  More articles by Bill Robertie

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