Imp Strategy
IMPS - TEAM GAME
In a team game you and your partner sit N/S at one table,
and the other pair of your team sits E/W at the other table.
In team game scoring your score on a board is added to your
teammates score on the same board and coverted to International
Match Points (IMPS) using this scale:
0 - 10 = 0 220 - 260 = 6 600 - 740 = 12 1750 - 1990 = 18
20 - 40 = 1 270 - 310 = 7 750 - 890 = 13 2000 - 2240 = 19
50 - 80 = 2 320 - 360 = 8 900 - 1090 = 14 2250 - 2490 = 20
90 - 120 = 3 370 - 420 = 9 1100 - 1290 = 15 2500 - 2990 = 21
130 - 160 = 4 430 - 490 = 10 1300 - 1490 = 16 3000 - 3490 = 22
170 - 210 = 5 500 - 590 = 11 1500 - 1740 = 17 3500 - 3990 = 23
4000 & over = 24
For example suppose you played in 4H non-vul and made it for +420
and your partners at the other table defended 3H making 4 for -170.
We add the 2 scores 420 + (-170) = +250 which on the scale is
+6 imps. We gain 6 imps on this hand, and the opponents loose
6 imps. Now for how this affects our strategy:
BIDDING
1. Part scores: Strive to get a plus score. Lets consider the situation
where we are bidding spades and opponents clubs and the
opponents push the auction to 3C. Our problem is whether
we should defend 3C or bid 3S. The other table will have
the same problem so we must consider the possibility that
one table bids 3S and the other defends 3C:
our their
table table
- 3S makes 3C makes +140 + (+110) = +250 = 6 imps
- 3S makes 3c down1 +140 + (- 50) = + 90 = 3 imps
- 3C down1 3S makes + 50 + (-140) = - 90 = -3 imps
- 3C down1 3S down1 + 50 + (+ 50) = +100 = 3 imps
- 3S down1 3C makes - 50 + (+110) = + 90 = 3 imps
- 3s down1 3C down1 - 50 + ( -50) = -100 = -3 imps
- 3C makes 3s makes -110 + (-140) = -250 = -6 imps
- 3C makes 3S down1 -110 + (+ 50) = - 90 = -3 imps
Notice that when our table is plus (first 4 examples)
we win imps in 3 cases out of 4. When our table is
minus (last 4 examples) we loose imps in 3 cases out of 4.
The same is true for our partners at the other table
(when they were plus we won imps 3 times out of 4).
So in general your part score bidding should aim to
create a plus, the size of the plus not being that
important.
2. Games: When vulnerable try your best to get to game. It goes
1S-3S limit from partner, and you hold a minimum type
hand. Should we bid the game? Let us consider one
table in 3S, the other in 4S.
our their
table table
- 4S makes 3S make4 +620 + (-170) = +450 = +10 imps
- 4S down1 3S makes -100 + (-140) = -240 = - 6 imps
If the game depended on a finesse (50%) then we would
expect to gain 2 imps per hand by bidding the game when
vul. We should actually be in all vul games that are
37.5% or better (3/8, 3 times we win 10 imps, 5 times we
loose 6 imps). It is impossible to judge this
percentage in the bidding, so we just stretch as hard as
we can to bid any vul game which may have a chance.
So to answer the question, yes, bid the game with a
minimum.
Compare this with not vul.
- 4S makes 3S make4 +420 + (-170) = +250 = + 6 imps
- 4S down1 3S makes -50 + (-140) = -190 = - 5 imps
Here its just about 50 / 50 so we should only bid
games which are about 50%, or in other words bid normally
and only accept invitations if you think its right.
Small Slams: Whether vul or not, only bid slams that are 50% or better.
VUL
- 6S makes 5S make6 +1430 + (-680) = +750 = +13 imps
- 6S down1 5S makes - 100 + (-650) = -750 = -13 imps
NOT VUL
- 6S makes 5S make6 + 908 + (-480) = +500 = 11 imps
- 6S down1 5S makes - 100 + (-450) = -550 = -11 imps
Grand Slams: Don't bid grand slams unless you are reasonably
sure they are making.
VUL
- 7S makes 6S make7 +2210 + (-1460) = + 750 = +13 imps
- 7S down1 6S makes - 100 + (-1430) = -1530 = -17 imps
NOT VUL
- 7S makes 6S make7 +1510 + (-1010) = +500 = +11 imps
- 7S down1 6S makes - 50 + (- 980) = -1030 = -14 imps
Since you stand to loose more when a grand goes down
then you will gain when it makes, you want to be fairly
certain it is making. (Vul 17/30 = 57%, NV 14/25= 56 %)
Sacrificing: Lets assume we are contemplating a 5C sacrifice over 4S
We examine some score comparisons
NV vs VUL (favorable)
- 5cx down3 4S makes -500 + (+620) = +120 = 4 imps
- 5cx down3 4s down1 -500 + (-100) = -600 = -12 imps
- 5cx down2 4S makes -300 + (+620) = +320 = 8 imps
- 5cx down2 4s down1 -300 + (-100) = -400 = - 9 imps
If you judge the sacrifice will go 2 down then your
potential gain of 8 imps is about equal to the potential
loss of 9 imps when their game wasn't making. So here
it is probably worth taking the sacrifice as they may
well bid 5S (more on this later) where you might beat it.
When you judge it will go 3 down however, you only stand
to gain 4 imps, but loose 12 if 4S wasn't making. And
remember that when vul, we stretch to bid those 40% games.
In this case its probably best to pass and defend.
Conversely, when the opponents sacrifice against your 4S
contract, if you have stretched your values at all to get to
game you should be delighted to double. Even if you
haven't stretched, double will be preferred more often
than not, as it is better to potentially loose 4 imps than
loose 12 imps by bidding on and going down.
DECLARER PLAY
Since overtricks are worth only 1 imp and going down in
a game contract can cost 10-12 imps, we play as safely
as possible to make our contracts and pay little attention
to overtricks.
DEFENCE
Again, since overtricks are worth little, the object of the
defenders play is to beat the contract.
Compiled by Lorne Russell 2005