This month, we examine jump overcalls such as:
If you have used a time machine to bring you and your computer back to 1950, you had better be prepared to play such jumps as strong. However, as all of you are reading this in the 21st century, you can expect such calls to be weak. (There is a small minority that treats these jumps as "Intermediate" when vulnerable).
What are the requirements for this weak jump overcall? Let's keep this easy. If you would open a weak two-bid, then you can make a jump two-level overcall. If you would open with a three-level preempt, then you can make a three-level jump overcall. Vulnerability and suit quality are key. Here are some examples:
For Auction A (above):
K J 10 8 7 6
Q J 8 7
or Q J 9 8 6 2
K 8 2
J 9 2
or A Q J 10 7 6
8 7 2
If I were vulnerable, I wouldn't risk 2 on the second hand shown, but would do it on the first and third.
For Auction B (above):
8 7 2
K Q J 8 7 5 2
or A 2
J 8 2
Q J 9 8 7 6 2
9 8 7 2
K Q J 10 8 7
I prefer to have a 7-card suit for a three-level jump overcall, but would do so with the right 6-card suit--as in the third example. As usual, vulnerability is a big consideration. If I were vulnerable against not, I'd be afraid on all three of these hands. If I were not vulnerable, I'd gladly bid 3 on all of them. Everyone has to choose their own comfort level, usually consistent with your style for opening preempts.
What should your partner do after your preempt? This is easy. Follow the LAW! Raise to the proper LAW level--just as he would over your opening preempt. If you want more science, you can play that 2NT after partner's jump overcall is artificial. You can use it for Feature ("Front of Card"), or you can use it to ask for shortness. I find that this never comes up--not worth the memory strain.
Whatever you do, stay in character. if you are a sound preempter, don't change your style for jump overcalls. If partner expects you to have a good suit and a decent hand, don't start zigging and zagging.
Bonus for very experienced players:
ALERT: What does it mean if you jump overcallafter they have preempted? For example:
There is a good saying: "You can't preempt a preempt." Once your opponent has preempted, you shouldn't also be able to preempt. Therefore, the jumps in the auctions above don't show weak hands. They show good hands. How good? "Intermediate." This means about 16-18 in playing strength (more than a full opening bid) and a good 6+ card suit. So, on the first example, a 3 jump overcall would look something like: KQJ1097
In the second auction, without any special agreements, the jump to 4 would also show an intermediate hand with 6+ good clubs. However, many experts use this jump (to 4-of-a-minor) as a Roman Jump Overcall. You would need to discuss with your partner if you use this method. If so, a jump to 4 shows 5+ and 5+ in the other major. A jump to 4 is 5+ and 5+ of the other major. So, in the auction shown above, 4 would be 5+ and 5+. When using Roman Jump Overcalls, the cuebid (3) in the auction above is freed up to ask for a stopper. It won't be Michaels (since the Roman Jump covers the 5-5 hand). The cuebid would show a good hand (usually with a running suit) and requests partner to bid 3NT with their suit stopped.
Summary of jumps after their preempts: All such jumps show GOOD hands. Make sure you and your partner know if you are using Roman Jump Overcalls to 4-of-a-minor.