How valuable is a strong 2C opening?


Most common 'natural' bidding systems, such as Acol and SAYC, include at least one forcing opening bid, reserved for strong hands. In the two systems mentioned, 2C is generally used to show a very strong hand. But how valuable is it to reserve a bid for these kinds of hands?

It is undeniable that a strong forcing 2C opening is useful in certain situations, particularly when responder is very weak but distributional, and particularly when opener has a specific hand-type which does not require much space to show.

Advantages of opening a strong 2C:

Disadvantages of opening a strong 2C:

On the other hand, there are some situations where it must be advantageous to open a very strong hand at the 1-level, since the 2C opening can consume a lot of bidding space. For example, it is difficult to find a fit in a second suit, after opening a strong 2C.

Advantages of having to open a strong hand at the 1-level:

Disadvantages of having to open a strong hand at the 1-level:

Of course, the utility of a bid is not only defined by how useful it is in specific circumstances. The frequency of that bid is also important. Acol 2C openings are very rare, occurring on approximately 0.4% of hands.

The expected gain of choosing to play the Rough 2C rather than the Acol 2C could be expressed as:
          {expected gain of the Rough 2C on one board vs passing} x {frequency of Rough 2C}
                      - {expected gain of the Acol 2C vs opening at the 1-level} x {frequency of Acol 2C}

The frequencies have been estimated elsewhere at around 4% and 0.4% respectively, and being conservative, my personal experience suggests an expected gain of 0.5 IMPs per board for the Rough 2C. The arguments above would suggest that you don't lose too much by not having an Acol 2C available, perhaps only losing a game swing (10 IMPs) once every 10 boards -- i.e. losing an average of 1 IMP per occurrence. If you believe my calculations, then this means that the expected gain of playing the Rough 2C instead of the Acol 2C is around 16 IMPs per 1000 boards played - not a great deal!

A less conservative player than myself might give the Rough 2C more credit, and say that it expects to gain 1IMP per occurrence, and furthermore that the Acol 2C isn't all it's cracked up to be, and it doesn't gain anything in the long-run. In this case, the expected gain of playing the Rough 2C instead of the Acol 2C is around 40 IMPs per 1000 boards played, or 1 IMP in a 25-board match.




You can contact me (if you ignore the inverted commas) at:   ben "at' rough2s "dot' info

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