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Today you are going to introduce the last
modification to the rules of the game: that which allows over-bidding
by the "defence" against game or slam contracts bid by the opponents.
Very obviously, to avoid defending at all costs, you must introduce the
notion of punishment for under-tricks, and speak about the rules of over-bidding
by the attacking side (advice23.3).
The theoretical content of this lesson is therefore important and difficult
at the same time. Take the time to present it carefully. For once, the
playing of the cards in the deals of the day will be secondary …
Start the lesson with a reminder of the
value of vulnerable and non-vulnerable game bids; then ask your pupils
by how many tricks the side who is not bidding the game contract could
go down and still make a profit, depending on the various vulnerabilities.
To help them, write the following table (advice
23.4):
| |
game |
down |
| not vulnerable |
420
|
50
|
| vulnerable |
620
|
100
|
Get them then to calculate that they could
allow themselves, not vulnerable, 8 or 12 under-tricks (!!) depending
on the opponents' vulnerability, and 4 or 6 under-tricks respectively
(which is still enormous) if they are vulnerable.
Get them to accept the idea that if you
had the right to over-bid like this the game would become impossible:
then explain to them that there exists a different scale for going down,
adapted to these situations. To use it, the declarer who had bid the contract
to win it (advice 23.5) must
double the opponents' sacrifice bid. Then give the detail of the
"cost" of doubled under-tricks.
| |
vulnerable |
not vulnerable |
| 1 down |
200
|
100
|
| 2 down |
500
|
300
|
| 3 down |
800
|
500
|
| 4 down |
1100
|
800
|
Which you can resume like this:
| - |
the first doubled under-trick costs
100 points not vulnerable, 200 points vulnerable; |
| - |
the following doubled under-tricks
are each worth 300 points vulnerable; |
| - |
the second and third under-trick doubled
not vulnerable cost 200 points, the rest 300 points. |
Now compare the respective costs of doubled
under-tricks not vulnerable and vulnerable and the values of different
game bids, by making two small tables:
I - The side bidding
for game is not vulnerable:
| His contract is worth |
Down costs
|
| |
Not Vunerable |
Vunerable |
| - 1 |
100
|
200
|
| - 2 |
300
|
500
|
| - 3 |
500
|
800
|
| - 4 |
800
|
1100
|
Not vulnerable, you can go down by two
doubled tricks with profit, only by one if vulnerable.
II - The side
bidding for game is vulnerable:
| His contract is worth |
Down costs
|
| |
Not Vunerable |
Vunerable |
| - 1 |
100
|
200
|
| - 2 |
300
|
500
|
| - 3 |
500
|
800
|
| - 4 |
800
|
1100
|
This time, going three down not vulnerable
is profitable, as is two down vulnerable. On condition of course that
the opponent would make the contract that he has bid !! (advice
23.6).
Once your pupils have understood the mechanics
of "sacrifice bidding", you can explain the rules of valid over-bidding
in Minibridge:
| 1) |
When one side spontaneously
bids a game contract, the opponents nonetheless communicate the usual
information (advice 23.7). |
| 2) |
If the "defence" player
discovers a fit in his side and in this case only, he bids the contract
which the Decision Table would allow him to bid if the opponents hadn't
over-bid. He then counts the difference in tricks to the level he
must now play at and, calculates that he will go down doubled by
this number of tricks. |
| 3)
|
He evaluates the cost
of his likely failure and compares it with the value of the opponents'
contract. |
| 4)
|
If the cost of failure
is higher than the opponents' game, he has no right to over-bid. |
| 5) |
But if it is the opposite,
he must "defend" (advice 23.8). |
| 6) |
In this latter case the
ball returns to the bidder of the attacking side: |
| - |
if his number
of DH points lets him bid at the next level, he must do so: he has
been "pushed". |
| In this case
the bidding continues, the defending side still having the right to
over-bid (advice 23.9). |
| - |
in the opposite case,
he doubles, which closes the sequence (advice
23.10). |
This
procedure is going to seem extremely complicated to your pupils. Illustrate
it immediately with a concrete example:
| - |
North is dealer; he bids a contract
of 4 , vulnerable. |
| - |
The bid comes to East who discovers
a nine card fit in Diamonds and 25 DH points in the two hands. He
is not vulnerable. This strength allows him to hope to win 3 ;
he must bid 5
over 4,
so he is short by two tricks. But two under-tricks doubled, not vulnerable,
cost 300 points, whereas the game in 4
would give North-South 620 points. So he must defend in 5. |
| - |
North can still bid. If his side
only has 27 to 29 DH points, he cannot take the risk of over-bidding
to 5, and
must double. If his side has 30 to 32 DH points, he bids 5(advice
23.11) |
| - |
At 5
East makes the same calculation, counting on losing by one trick more
than the last round. This nonetheless allows him to bid 6©
(risk of 500 against 620), whereupon North can do nothing other than
double. Whew!! |
Quick, get them to play the deal of the
day
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