This could improve your slam bidding if you still cue bid your aces first . Even old hands who already use it may find that you don't know it all!
'Cue bidding,' as used in this title, should more properly be called 'control bidding' but I'm afraid the old phrase is ingrained. In this context, it means bidding a suit, not to indicate that you may wish to play in it, but merely to show a degree of control. Aces and voids are 'first round controls'. They ensure that you need not lose the first trick in a suit contract. Kings and singletons are 'second round controls'. They stop you losing the second trick if you do lose the first. When I was first taught cue bidding I was taught to show first round controls before second round controls and often you could not show all of your controls because of lack of bidding space. In the Italian method, however, you show first or second round controls in the cheapest possible manner, showing a king in a lower suit before an ace in a higher suit for example. This conserves bidding space but now you don't know how many first round controls you have so you also need to use a control asking bid such as Blackwood to check this. I use 4NT Roman Key Card Blackwood but you can use any method that you are comfortable with. I will explain Roman Key Card Blackwood and its many variations in a later blog.
Look at these two hands: The bidding starts 1H - 1S and opener is thinking of game but partner may have only 4 spades and 6 points so, even with this 5 loser hand, opener should content themselves with a game invitational 3S bid. (Give responder 4 spades, 2 hearts, Kxxx in diamonds and QJx in clubs if you don't believe me.)
Responder is much more than minimum, however, and should be thinking of a slam when partner opens the bidding and certainly now that a fit is found. By bidding 3 spades partner is showing a non-minimum hand around 15-17 total points. Responder has 18 high card points and is well into the slam zone. With first or second round controls in every suit and with the lead coming up to his hand he is in no danger of losing two quick tricks and hence he can bid 4NT directly (though more experienced players may prefer to cue bid in case they can find a grand slam). Playing Blackwood or Key Card Blackwood he would get the response 5H showing 2 aces or key cards. Playing Roman Key Card Blackwood, however, he gets the response of 5S showing 2 key cards and the queen of spades. This is quite important on this hand since you know you are missing an ace. If you only have an 8 card fit you need the queen of spades from partner to avoid a finesse. With the AKQ of spades 6S is a good proposition.
Recap: 1H - 1S - 3S (game invite) - 4NT (RKCB) - 5S (2 key cards + Q trumps) - 6S. No cue bidding.
Now, after 1H - 1S - 3S responder can see 2 quick losers in diamonds and needs to know opener's controls. They must start cue bidding. Whether using old fashioned or Italian cue bidding, responder would cue bid 4C. By not raising 3S to 4S partner knows that you are interested in a slam and have started cue bidding.
Using old fashioned cue bidding, opener would now bid 4H, showing his ace of hearts with his first cue bid. This leaves partner in a quandry. He will be committing to playing at the 5 level if he bids 4NT. Opener has denied the ace of diamonds but he may have the king or a singleton. Should he press on and gamble on not having two losing diamonds? Remember the opponents are listening so they will know that opener doesn't have the ace of diamonds and may easily find the right lead.
Recap: 1H - 1S - 3S (game invite) - 4C (Slam interest. 1st round control cue bid in clubs) - 4H (1st round control cue bid. Ace of hearts not void since suit bid earlier) - 4NT (RKCB gambling on a diamond control from partner or a favourable lead) - 5H - (2 key cards) - 6S gamble.
Using Italian cue bidding, however, opener would bid 4D after 1H - 1S - 3S - 4C to show their singleton in diamonds, a second round control, before their ace of hearts since this is their lowest control bid.. Responder doesn't know whether this is an ace, king, singleton or void but at this stage it doesn't matter. He now knows he doesn't have two quick losers in diamonds and hence can continue to investigate a slam. 4NT reveals the missing ace so responder settles for 6S.
Recap: 1H - 1S - 3S (game invite) - 4C (Slam interest. 1st or 2nd round control in clubs) - 4D (1st or 2nd round control in diamonds) - 4NT (RKCB knowing not 2 quick losers in any suit) ) - 5H - (2 key cards) - 6S (knowing not two quick losers in any suit).
Now responder has no control in clubs so the bidding starts 1H - 1S - 3S - 4D. Using old fashioned cue bidding, 4D merely denies the ace of clubs or a void but in Italian cue bidding it denies any first or second round control in clubs. Opener knows immediately that they have at least two club losers and that he must sign off in 4S.
Recap: 1H - 1S - 3S (game invite) - 4D (Slam interest. 1st or 2nd round control in diamonds but no 1st or 2nd round control in clubs) - 4S (no slam - I have no club control either).
With this hand, however, opener is rather pleased to hear that responder has no ace or king of clubs since this means they are more likely to have the diamonds well covered. After 1H - 1S - 3S - 4D opener can bid 4H which, perhaps surprisingly, guarantees that they have a control in clubs.
Cue bidding to show a control in a different suit doesn't come naturally to most people but it is logical if you think about it. As we saw in the previous hand, opener, without a control in clubs himself, knows from responder's 4D bid that they have at least two club losers and he has to bid 4S (game) to sign off. The only way that opener can show his control in clubs is by not bidding 4S. Making the cheapest non trump suit bid therefore shows a control in clubs but says nothing about heart controls. After a suit has been skipped in the cue bidding (clubs here) then the cheapest bid in a non-trump suit (4H) shows a control in the skipped suit (clubs). Knowing that he doesn't have two quick losers in any suit, responder can continue the slam investigation with 4NT and easily bid to 6 spades.
Recap: 1H - 1S - 3S (game invite) - 4D (Slam interest. 1st or 2nd round control in diamonds but no 1st or 2nd round control in clubs) - 4H (don't worry, I have a control in clubs) - 4NT (RKCB that's OK, I've got the rest stopped) - 5H (2 key cards + Q trumps) - 6S (since he doesn't know opener's club control is a void).
Actually, a grand slam can be made with this last deal but bidding it with any certainty requires opener to take the initiative after responder's 4D shows a diamond control. At this point, opener already knows that they do not have two losers in any suit and that they have additional values themselves that are difficult to convey to partner. They have 6 hearts, not 5, as a possible source of tricks and a void, not a singleton in clubs If opener bids 4NT then responder will bid 5H showing 2 key cards. Since they have denied the ace of clubs then these two controls must be the ace of diamonds and the king of spades. That's only 7 points and partner was interested in a slam. They can only have 3 points in clubs since they don't have ace or king so they must have points in the red suits but do they have kings? You can bid 5NT to ask for kings since you now know you have no first round losers in any suit. When partner shows two additional kings they must be the red kings since they have shown the king of spades and denied the king of clubs. 7 spades is therefore a reasonable proposition with 4 spades, 6 hearts, 2 diamonds and a club ruff. If you need to ruff a heart to set the suit up this is one less heart trick so you will need to ruff two clubs.
Recap: 1H - 1S - 3S (game invite) - 4D (Slam interest. 1st or 2nd round control in diamonds but no 1st or 2nd round control in clubs) - 4NT (RKCB don't worry, I have a control in clubs and a control in hearts) - 5H (2 key cards which have to be A diamonds and K spades) - 5NT (king ask) - 5H - (2 kings which must be the red kings) - 7S (can pretty much count 13 tricks on non-outlandish breaks).
I have included the grand slam discussion to show how Italian cue bidding allows detailed inferences to be drawn that may allow a grand slam to be bid with a limited point count. The inferences from partner not being able to show a first or second round control can be crucial. Don't worry too much about grand slams, however, bidding small slams is much more important in normal club bridge.