Control Showing/Asking Bid 
See May 2019 Bridge Bulletin p.27
Exploring for stoppers: asking and telling


Looking for a Stopper for Notrump

    Opponents have bid a suit:
      A cuebid of the suit an opponent has bid (when the bidding has primarily been your sides') asks partner for a stopper in that suit, even if there is a second unbid suit.

        Example:  

          1  (1)  1
          2   (P)   2  
          Where 2 asks partner for a stopper in hearts. 
          Mel Colchamiro says to bid 3NT (if that's where you were aiming)
          even without a stopper in clubs (the 4th suit) because hearts are the
          most likely to be led, plus partner may have hearts stopped.


    Opponents have not bid...

      ...and your side has bid three suits, a bid of the unbid suit asks for a stopper in that suit.

      ...and your side has bid two of the four suits, a bid of one of the two unbid suits shows a stopper in that suit and asks partner for a stopper in the fourth suit.

Exploring for Slam

    Ace asking bids, such as Roman Key Card 1430, should not be used if you have 2+ cards not headed by an ace or king unless partner has already made a control bid showing one of those cards or if you have all but one ace or key card.

    Instead, Control Showing/Asking bids should be used.

    2N may be used to show A or K in the agreed trump suit, such as 1S-2C, 2H-2S, 2N.

    Here is a hand from the Feb. 10, 2020, Weekly Bridge Quiz, #5:

      K7432-QJ2-A9-A32

      Bidding: 1D - 1S, 4S - ??

      The pro who created the quiz said: "Partner has a balanced hand (no Splinter Bid) worth 18-19 points. Slam prospects are good, but the next move is not clear. We like a control bid of 5 Diamonds. If Partner gives you a 5 Heart call, bid the slam."

      Yet 42 people bid 4N,  19 passed,  8 bid 5,  and only 2 made the correct bid of 5

    Here is an example from Billy Miller's column in the November 2019 Bridge Bulletin, p. 63: 

      The hand was not given, but the bidding went 
          N    S
        1  1
        3  4 = control showing
        4   ...  and ended up in 5 down 1.

      The problem is that both partners had worthless spade doubletons.

      Billy pointed out that control bidding starts with the cheapest suit, so by passing over 3 to bid 4, S denied a spade control, thus N's failure to sign off in 4H indicates that he does have a spade control since otherwise they would be off 2+ spades off the top.

      In fact, Billy says that the primary purpose of the 4 bid is to show the spade control (since bidding 4 would go past the heart game) and that it does not necessarily promise a diamond control because without one, any further noise [other than to bid game] would be futile.

      The 4 bid not only shows a spade control, but suggests a diamond weakness since with a diamond control as well as the spade control, N would have bid 4N Blackwood instead of 4. (N shouldn't have a singleton of void in diamonds since he didn't splinter rather than bidding 3.)

      However, if S has a diamond control, he could now bid Blackwood, knowing that his worthless spade doubleton is covered, or without a diamond control, S could bid 5 to ask again for a diamond control.

    Non-Serious Slam Try

      Bidding a non-jump 3N after agreeing on a trump suit: 1S-2D, 2H-3H, 3N.
      Sometimes the 3N bidder may think that 3N will score higher than 4H (if both contracts can take 10 tricks). That is usually because he has some extras in HCP, but not enough extras to bid for slam.

    Serious Slam Try

      Bypassing 3N is a serious slam try: 1S-2D, 2H-3H, 4C/D/.
      This raises the question of whether a subsequent of 4N is a correct back to NT because partner did show a needed control, OR does 4N ask for aces?

Control Bid, Game Try, or Search for a 4-4 Spade Fit After a 5-4 or 5-3 Heart Fit Has Been Found?

    Image This hand (South's) and bidding are from It's Your Call in the Jan.2021 Bridge Bulletin, page 40. Is South's 2 a Control Bid, a Help Suit Game Try, or exploring for a 4-4 spade fit?

    North's immediate raise of hearts could be made with 3 hearts and it's South responsibility to make a bid which would indicate that he only has 4, if that is the case, such as bidding 2N.

    There are a lot of variations of "game tries". If you have not discussed them with a new partner and this sequence comes up, it's probably safest to play 2 as a Help Suit Game Try to which North bids 4 with 3-4 cards in spades (in this example) with at least 1 of the top 3 honors; otherwise, he bids 3.

    We saw above that Billy Miller considered the spade bid after agreeing hearts to be a control bid and not a game try nor a 4-4 fit try.

    Having said that, it should be noted that in the hand and bidding above, most of the experts considered 2 to be a search for a 4-4 fit..

    Why look for a 4-4 spade fit? Manice Molson said We might need the 5th heart for a pitch.

    But the real answer depends on what you and your partner have agreed 2 means in this context.