If you overcall on a four-card suit at the one level, what are your chances of success?

Note that there is a major caveat here: are you smart enough to know when it would be a good idea to overcall with a 4-card suit? To answer that, I humbly suggest you look at the individual hands you get, as there are not so many of them. You may decide that there is some further test you yourself would apply that distinguishes the sheep from the goats (ie when you would and when you would not).

Just to recap here are the previous tutorials:
 

Day 1

Day 2

Day 3

Day 4

 

Open >= Bid 1C
Open <= Bid 1D
Over >= Bid 1D
Over <= Bid 1S
Over >= Shape 4333
Over <= Shape 4441

This guarantees you overcalls at the one level made with no more than a 4-card suit in the overcalling hand.

If you're curious, you can restrict vulnerability too (over on the right). I leave this as an exercise, and am guessing it won't make a huge difference to the results.
 

a. You can look at the headings of the columns in this table change as the sequences are tabulated.
b. You can watch the numbers cumulate in the Bid Analysis tab.

What you will notice is that within a given file (ie time period) you first see all the hands where 1C was overcalled by 1D, ordered by time/date. Next you will see the hands where 1C was overcalled by 1H, and so on, ending with the hands that were opened 1H and overcalled 1S.

In addition, you can double click a hand as it scrolls by in the upper box, to see if it fits the conditions you thought you just inserted. A reality check! Given #6 above, the overcalling hand should always be at the bottom of the screen.

NOTE 1 (I should have mentioned this before) you may order the results by clicking any one of the columns on the main results window. Experiment to see what happens if you click a column twice. If there are lots of results (here it doesnt matter), it may go a little quicker if you leave it unsorted - to do this simply click the column marked "Index".

NOTE 2 If this is taking too long (you have a slow connection), you may want to stop the search. However note that your results will be limited to the bidding sequences you already looked at. So it's not a particularly good idea. 

Let me give an example. Suppose you let it run through all the 1D overcalls (the opening must, perforce, have been 1C) and now you see BRBR producing records showing that the overcall is 1H. You press stop. The problem (not insurmountable but this is left as an exercise for the experienced jockey) is that in the column of 1C openers there are two kinds of hands, those overcalled 1D and those overcalled 1H. 

Not a problem, you say? Maybe not, but the general principle is that BIDDING searches must be allowed to finish, particularly where the averages in one cell in the Bid Analysis table (or Hand stats) contain more than one bidding sequence. If not, the results may be badly biased since the "higher" sequences are always missing (eg. the ones that end in grand slams).

NOTE 3 You may decide you don't want to slow up the search by putting the individual hands in the main display. Simple go to the "Bid Analysis" tab and check "No listing". This can safely be done in the middle of a search.

If you decided that this is all too slow (running over the net), you can

a. stop the search and try using the data as is (see the warnings above)

b. skip to part 2 of this article where the original Frank Stewart question is examined - there's a lot less data to look at.

c. restrict your search to one of the overcalls only (eg 1C overcalled by 1D. or direct overcalls of 1D,1H,1S after 1C opening).

d. get hold of a BRBR disk from us. Unfortunately we have to charge (:

e. look at the summary of the results only. I have saved the spreadsheet as a .CSV file here

Most folks connected to the internet in USA and Canada, especially New England, will find this to be easily fast enough, however.

1. Here is what the "Bid analysis" tab looks like on my screen. If your screen is big enough, stretch the window downwards by grabbing the bottom, thus:

Note that the  "slider" above the table is set to "Interv". This is a LOT of data. We searched over 450,000 hand records and got almost 19,000 4-card overcalls.
 

All of these numbers can be viewed interactively by holding the mouse over the cell in the table, if you don't feel like messing around with a spreadsheet. However the curious of you will surely want to do just that, mess around.
 

Now press the button marked "View Duplicate" (I already did this in the illustration) and you can look through all the other plays (usually at least 52) of the same board. To restrict yourself to those opened 1C, you can sort by "Opn" (the last column) by clicking on it, and choose only those results where the last column says "1C'. In the example, you can see all the hands that were opened 1C and then the first 2 that were opened 1D. Interestingly, on this hand, NO 4-card overcalls were made against 1C* (* means alert recorded, so presumably Precision 1C or Polish strong 1C).
 

4. On the Bidding tab set:

a. Open >= Bid 1C
b. Open <= Bid 1D
c. Over >= Bid Pass
d. Over <= Bid Pass
e. Resp >= Bid 1D
f. Resp <= Bid 1H
g. Advc >= Bid 1H
h. Advc <= Bid 1S
i. Advc >= Shape 4333
j. Advc <= Shape 4441

And repeat the search, following steps 5,6, and 7 above EXCEPT that the view seat (step 6) should now be set to "Advancer". This won't affect the numerical results, though, since Advancer is partner of Overcaller!

You'll probably want to put the slider in the Bid Analysis table over "Adv", though this can be moved at any time without problems.

Here's what I got (it's a much smaller data set so you may be more inclined to try it first if the search at the start was tooooo sloooooow):

And I saved the report

Everyone should be able to try this smaller search.
 

Direct second-seat 4-card overcalls do not lose significantly.

Advance seat 4-card overcalls at the one-level after a one-level responding bid, are a fairly significant winner. However I would emphasise that it may be a good idea to look at the hands, so you can see what exactly inspired the successful overcallers to bid. After all, it could simply be that only good players bid thus. This is a circular argument - to become a good player, you have to bid so?

I hope this is useful. Please write to me and tell me what you didn't understand.

Here's the email again

recsoftware@microtopia.net

Stephen Pickett

that address again:

http://www.microtopia.net/bridge/downloads/online.exe

2. Here is the URL of the Frank Stewart article. Only works if you are an Okbridge member, I think.

3. Here is Day 6 - "With no singletons or five-card suits, if you have a 4-4 major suit fit, should you prefer 3NT or 4 of a Major?"