Ken Rexford, Cuebidding at Bridge said:
When I set out to write this book, the motivation was not truly to reinvent the wheel, but perhaps that was, in a sense, the result. I researched multiple sources for clues as to what ‘Italian-Style Cuebidding’ means. (By ‘Italian’, I mean that approach to cuebidding that has its origins in the theory of the Italian Blue Teams of World Championship fame.) The works of Giorgio Belladonna, including Cuebidding to Slam, coauthored by Claudio Petroncini, published in 1990 and translated by Daniel Neill of Kentucky in 2004, served as a starting point, perhaps reflecting the ‘old school’ theories of the originators. For the ‘modern’ perspective, I reviewed a series of three articles by Fred Gitelman, “Improving 2/1 Game Force”, published originally in Canadian Master Point magazine.
Neither of these two texts showed me a functional wheel and the theories were at points inconsistent with each other. In short, it was a mess. Just look over Vugraph Archives to see for yourself. The professionals might all agree what to open, what to respond and what to rebid, but their cuebidding sequences diverge on to all sorts of strange paths.
I delved deeper, reading brief notes in bridge books, reviewing system notes for many of the great players and conducting online research. My online studies referenced numerous lesson notes, commentaries and the like. I even posed questions on bridge forums for the masses to respond to. Finally, I turned to professional friends of mine, discussing the issue between rounds over cigarettes. My major source here was my friend Kenneth Eichenbaum of Columbus, Ohio. The result was a mismatched collection of majority views, minority views, insane views and sometimes no opinions or views at all.
The full answer is: people are making it up as they go, even at very high level. There are numerous sources out there with partial insights - I've even written on this topic myself over the years - but then there are other sources which will claim the opposite. Currently there is no coherent approach to control bidding, or at least none that sees significant play. Beware anybody trying to sell you the cure for slam bidding problems.
Personally I have some suggestions that I think are very valuable and help me bid many good slams where the field will fail.
- Have good agreements about which auctions set up a game force. Have many such bids available in your system at a relatively low level in the auction.
- Do not jump with strong hands. Taking it slow gets you more information. This may not only prove vital for finding a good slam or staying out of a bad one, it will also make it easier for partner to later evaluate their hand in context of what they have already shown. If we look at it from a purely information-theoretic perspective, we have 32x more auctions starting with a non-jump bid compared to those starting with a jump in the same strain. Provided that the cheaper bid is forcing, and if our intent is to maximise the amount of information conveyed, we should therefore only jump on approximately 3% of hands. In practice the number is higher - people use the bidding space far from optimally, so 5% or even 10% is tolerable. Any more than that and you're preempting partner on strong auctions.
- Hand evaluation is vital for slam bidding. More tools or gadgets are nice but won't get you there by themselves. In my experience, the most common hand evaluation skill level lies somewhere between 'could be better' and 'atrocious'. For slam bidding in particular this is very important.
- Keep in mind that asking for key cards is a tool for staying out of bad slams, not a gadget for finding good ones. You should only ask for key cards once you are confident you can't learn anything important instead. I pair this with the rule 'jump bids do not ask for aces', which rules out most forms of Exclusion, Kickback and also means 4NT is not RKC on many auctions. Most people are far less extreme in this, but I believe their slam bidding is proportionally worse for it.