In this series, we are analyzing 1,000,000 deals which were played on-line. These deals cover a wide range of level of play and were provided by Stephen Pickett with Bridge Browser.

What is the most likely opening bid?

Let's start at the very beginning: 1 is the winner. Of course, some of this is influenced by system. Players using a strong club system open 1 on all good hands. Balancing that out to some effect, is the fact that they also open all minimum hands (that don't fit 1NT or 1MAJ) with 1.

1 was opened on 22.7 % of all deals, just slightly ahead of 1 on 21.31%. So, the opening bid is 1 of a minor on almost half of all bridge deals!

Some questions with logical answers:

Which is more likely to be opened: 1 or 1? Logically, there is an equal chance of getting dealt 5 spades or 5 hearts. However, a 1 opener is more likely for two reasons: 1) with 5-5 you open 1 not 1, and 2) Since some people use the Flannery convention (whereby a hand with 5 hearts and 4 spades is opened 2), that slightly cuts down on the number of 1 openers. The data bear this out, as 1 was opened roughly 7,500 more times than 1 on the 1,000,000 deals.

Here's another question with a logical answer: Which is more likely--a 3-of-a-minor opening or a 3-of-a-major opening? Since most people use 2 (and a few use 2) as conventional, there is no way to open weak two bids there. That puts more weight on the 3-bid. Conversely, most players can preempt on the 2-level with a major, so there should be fewer 3-level preempts in majors. Again, the data correlate. A 3-level preempt in a minor occurred on 37% more deals than a 3-of-a-major preempt.

For the curious-minded, here is the full report--there are even more logical conclusions that can be drawn.

OPENING	% out of 1 MILLION DEALS
1	22.68
1	21.31
1	15.54
1	16.31
1N	11.68
2	2.02
2	1.32
2	2.02
2	2.05
2N	1.85
3	0.69
3	0.68
3	0.52
3	0.47
3N	0.10
4	0.04
4	0.05
4	0.32
4	0.27
Higher	0.08