Vincent Brévart

Vincent Brévart

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Understanding the comparison

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Principle of comparison

When you play a deal during a game, you control the hand of the player sitting South. The three players sitting North, East and West are controlled by the computer, which makes them play independently using the same playing engine. At the end of the deal, you often ask yourself the following questions:

  • What result would the computer have obtained by controlling South's hand?
  • Did I play much better than the computer would have done in South?
  • Could I do even better by playing differently?
  • Could I win this deal that I lost?

To answer all these questions, you have to compare the deal by having it replayed by the computer with control of South's hand. In my 4 software programs, this has been called the comparison. To start the comparison, all you have to do is click the large Compare deal button which is displayed at the end of a deal, provided however that the comparison has been enabled.

Compare deal

To enable the comparison, use the Preferences menu, or open the general preferences on the Play / Comparison page.

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Studying the comparison step by step

The comparison is performed quickly. The cards are played one after the other, without stopping. Because - and you will realize it when you use it - it is not always necessary to study in detail a compared deal. If the deal is easy, you can imagine that the computer has made decisions not far from yours, and that it is not really useful to study his way of playing. On the other hand, once you have been informed of a very different result made by the computer, and you want to know how he played the deal, you can study the comparison step by step using the progress buttons:

Boutons de déroulement

You can then go back to the first bid or the first card, and see all 4 hands. A right click on the table brings you up along the plays, a left click brings you down. Ctrl+click does the same thing but from trick to trick. You can thus see how the deal was played during the comparison.

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Understanding the computer's choices

To more easily understand the computer's choices, you can then click the Explain decision button. A short explanation will tell you what the computer's intention was when playing. Note that he may be wrong and play badly, but this will not prevent him from explaining with self-assurance what he was trying to do.

Explain decision

You can also know what the player on lead knows about the other three players, with 3 degrees of reliability (100%, 90% and 70%). To do this, click the Player's visualization button. By clicking on All, you will display the vision that a spectator would have who would not see any of the hidden hands. This vision is used by a player to know for example what his partner knows about him. In the 90% vision shown below, South knows that North holds the Ace of Spades. He can also know that a player does not have this or that card (the card is then crossed out).

Player's visualization
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See the differences of choice

But often we want to know when the computer in South made a decision different from the one we made ourselves. For that, we need to restore the deal as we played it the first time. This is done by clicking the Restore the deal counting for the game button.

Restore the deal counting for the game

This button allows you to restore the deal as you played it in South the first time. Once the deal counting for the game is restored, you just have to go back to the most important plays and see the differences of choice between user and computer. For example, the image below shows that the user played the Queen of Spades (selected card), while the computer would have chosen the Ace (the card has a colored frame - green on the image).

See the differences of choice

You have to make the difference between the selected card (which is the one you played the very first time), and the card that the computer would have chosen. The two cards may be identical (the colored frame is then on the selected card), but they may be different (the colored frame is then on another card).

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Make the computer replay the contract you played yourself

In belote and bridge, the comparison can be played in a contract other than the one declared the first time. Now, we would often like to know what the computer would have done in the contract that we played ourselves. This is done in two clicks:

  1. Click the Restore the deal counting for the game button (shortcut F6).

    Restore the deal counting for the game This button restores the deal as you played it the first time, therefore with the contract that you played.

  2. Click the Make computer replay quickly button (shortcut F4).

    Make computer replay quickly By this button, the computer goes through the card play again, but not through the bidding. So he replays the same contract as you.

Afterwards, if you need to see the comparison deal again, click the Restore the comparison deal button:

Restore the comparison deal

Finally, once you have finished studying the deal and want to resume the normal course of your game, click the Stop studying deal button:

Stop studying deal
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The comparison points

To spice up the game, some comparison points are awarded to the user or the computer. These points are displayed in the scoring area, and are updated immediately after the comparison. The user's points are on the left, and the computer's points on the right (with the characteristic colored frame).

Comparison points 1

4 = User's total
2 = Computer's total (with the colored frame)

At the end of the comparison, depending on the result obtained, some points are added to the user if he did better than the computer, or to the computer in the opposite case. In the example below, the user did better than the computer and scored 3 comparison points. The total of each is then automatically updated.

Comparison points 2

+3 = comparison points scored by the user
His new total is 4+3=7

At the end of the game, whichever of the two (user or computer) has scored the most comparison points is declared the winner of the comparison. His total is framed in blue. Winning the comparison gives you the satisfaction of having played better than the computer, even if you didn't have very good hands and lost the game to your opponents.

Winner of the comparison

The user won the comparison by 15 points to 12

There are several ways to count the comparison points. The setting of the compared games is done through the general preferences on the Play / Comparison page. Read the associated help page for more information.

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The cumulative points of the computer

For games won on a total of points to be reached, it is possible that by adding up all the scores obtained by the computer during the comparison, the latter has already won or lost his game, while the user has not finished his own. This will be displayed as follows:

EW cumulative win

The computer in South would have already lost the game (East-West wins).

NS cumulative win

The computer in South would have already won the game (North-South wins).

As a result, if at the end of the game you get a display similar to the one below, you can be delighted because you won a game that the computer, if he had played in your place in South, would have lost!

U cumulative win

Congratulations to the user who won everything: the comparison (43 to 18), and
the game when the computer (with cumulative points) would have lost it!

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Game scores The scores button will show you all the deals of the game, with on each deal the score obtained by the user and the score obtained during the comparison (the latter, always in second position, will have a characteristic colored line). You will also see the detail of the comparison points scored by the user (U) and the computer (C).

Statistics The statistics button will show you your statistics for the current session, and your general statistics on all the games you played. You will also find your percentage gap. This one shows the difference between the user's winning percentage and that of the computer (if the comparison is enabled).

Example of statistics

Here is an example of statistics on 2903 games. The user wins 4.52% more
games than the computer. And you, what is your percentage gap?

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Special Belote

During the comparison, South does not always declare Rebelote

Yes, thanks to the comparison, we sometimes discover unexpected techniques that we were not used to. Some users would lose comparison points by always declaring Rebelote. But when a player is sure to go down, why would he give the opponents 20 points for free? You must therefore know how to spot situations where there is no more chance of winning, and then decide not to declare Rebelote. For that, use the tooltip displayed from the contract area:

Contract tooltip

The tooltip of the contract tells you if you have already failed to make your contract. But be careful, it is not enough. Machine players also know how to calculate if they are going to go down considering the tricks they think they still have to lose.

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Special Bridge

During the comparison, the opening lead is different and I am penalized

No, if the bids were strictly the same, the machine player always selects the same opening lead, whether on the deal played by the user or on the deal played by the computer in South during the comparison. The machine player takes into account his hand and all the bids made. If this information is the same, he will always make the same decision. However, if the bidding was different while leading to the same contract, it is quite possible that the vision of the first player has changed and that he then selects a different card to open the lead. That said, what happens even more frequently is that during the comparison it is not the same declarer who played the deal. And so it was not the same opponent who opened the lead. Hence obviously another choice for the opening lead, often with a different final result.

In SimiliBridge, the user is allowed to play North's hand when the latter is declarer. With the automatic hand rotation, the user keeps the same position at the bottom of the screen, while controlling North's hand. He then receives the opening lead from the opponent seated to his left, who is East (and not West). If during the comparison it is South who becomes declarer and he plays the same contract, we can have the impression that the player to South's left voluntarily changes his opening lead to make a better result and penalize the user. But it's just an illusion. Because then it is no longer East who opens the lead, but his partner West!

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I played better than the computer, and yet I lose the comparison

Yes, it's true, it sometimes happens because the comparison may be spoiled by a big mistake from the opponent. In South, as the user, you played the best you could, taking the only chance you had of winning. You lost, all right, but you couldn't help it. The only thing is, during the comparison, the computer played in a much more simplistic way, adopting a line of play that normally could not win. And, what a disaster!, there was a huge blunder made by East or West which gave South the win of the deal! Hence some comparison points that you lose, but quite unfairly, one must admit. It also happens to me from time to time, and I moan in these cases... It is therefore important to send me the deals to correct, whether the mistakes come from your partnership or from your opponents. Because the more the game is of a good level, the more the comparison will be fair and interesting.

Save deal as

Button to save a deal to a file

Click the Save deal as button to save a deal. For more information, read the section How to report a playing mistake.

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Contract belote and the Regina system