I hate to write about the history of bridge bidding, since it is rarely is germane, but on this topic it may help you understand where we are heading today and why. Since in Bridge, my actual history does not extend into the 20th century, I may be a poor one to write this, but my hearsay sources are good.
Back when cards were still shuffled, responding to partner’s overcalls with supportive hands was quite simple. They actually resembled the responses you would make to opening bids, so life was much easier. If you had 3+ card support and 6-9 hcps you raised partner’s overcall. If you had the same hand with limit raise values you jumped in his suit. If you bid a new suit, it was forcing one round. If you bid 1NT, you took the smile off partner’s face. Well, that part never changes.
That all worked well “back in the day”, so why make any changes. Here are my own observations. At that time, overcalls were really overcalls, you could actually lead partner’s overcalled suit and not give up a trick on defense! One level overcalls were expected to have at least 10 hcps, 5+ cards in length and a good suit with honor strength. Even a “space eater” like 1d/2c was expected to be an opening hand equivalent and probably a one loser suit. A 1NT overcall showed at least 16+ hcps and a double stop in opponent’s bid suit, and jump overcalls were as strong as overcooked morning coffee, you could take them to the bank for direct deposit. In that environment simple tools for searching for games worked well because overcalls were so disciplined. Actually, in the overcall seat “trap passing” with a big hand was a prominent strategy, and lead to light third seat openers.
The first development was “Sputnik.” If you know what Sputnik is in bridge terminology, it’s well past the time to give up the game. No, I am not referring to the Russian satellite, it’s actually the system we call "negative doubles" today. Alvin Roth invented it and claimed that it was the beginning of the space age of bridge. He was not too far from wrong, and many of his ideas form the basis for the 5 card major system we play today. As a result of Sputnik, everybody gave up their penalty doubles of overcalls (the primary policeman of sloppy overcalls) and joined the space age. At this point the pent up frustration of not being able to overcall on "pure crap" broke loose!! Overcalls started down the slippery slope and we may not have seen it all yet.
As overcalls got less disciplined (more diverse as my partners prefer to say) it became more important for advancer to be able to better describe the shape and strength of his hand to put overcaller in the driver’s seat. If advancer can precisely describe his hand, then overcaller can call the “shot”: Go or No Go.
A further development was the popularization of the “Law of Total Tricks.” Although Marty Bergen and Larry Cohen did not develop the theory, they put it on every bridge player’s menu. No longer did 1c/1s/p/3s mean a limit raise, it meant that we had 9 trump between us and a hand not good enough for a limit raise. The sequence 1c/1s/2c/2s no longer guaranteed anything other than 3 card support for spades. Since the LOTT changed the jump raise to make it preemptive, the cue bid in opener’s suit was put in play to show a limit raise or better with support. This is where most of my readers find themselves today.
It bothered bridge theoreticians that the Law of Total Tricks would have you raising a 1 spade overcall to three spades with QJxx, xx, xxxx, xxx and also raising to 3 spades on QJxx, xx KQxx, xxx. The first hand is clearly preemptive, but the second hand has some very constructive values as a supporting hand. Enter the Mixed Raise which I first read about in Larry Cohen’s “To Bid or Not to Bid-The Law of Total Tricks”. The Mixed Raise in competition is shown by a jump cue bid on the 3 level. So, 1c/1s/p/3c shows the Mixed Raise.
The first two requisites of the Mixed Raise are 4 card trump support and at least one doubleton. The more distribution the better, do not use it on 4333 hands. The final issue is points. Since the Mixed Raise is by definition less than a limit raise (which remains a simple cue bid) I prefer 7 to 9 support points. Examples might be 7654, A987, 6, QT87 and QJ98, A5, JT42, 763. Since partner did not double and then overcall, he could have as much as 16-17 hcps for his overcall. The jump cue bid is self alerting. If partner passes your cue bid, you know what to do. If partner just bids 3 spades, that shows no game interest. If partner bids game, well “you done good.”Pray he declares well.
With the uncertainties of overcalls in today’s competitive bidding, it becomes important to “slice and dice” advancer’s hand to define it as tightly as possible. Talk this over with your partner and add it to your arsenal. Even if partner gets confused and can’t remember what the double cue bid means, it has to be supportive and he has to bid something, so hopefully he will rebid spades and this will not end up in a bidding disaster. With 4 trump you wanted to compete to the 3 level anyway.
If you have a big storage tank, there are more slices and dices. If you want the full entree menu, write to me at firstname.lastname@example.org