Simulation bidding

Bridge programs usually use a set of rules for bidding, or a large database of bids. For example, if you are overcaller, and opener bids 1, there will be a set of rules that the program follows. One rule might be 'Bid 1 with 10 points and at least 5 hearts'. For a given hand, the program will always make the same bid because it steps through the same lines of code. Holding say Axx/KQJxx/Qxxx/x, it will always overcall 1 because that rule says to. The program will never change its 'mind'

SIMULATION bidding works differently. This crudely is what happens. After an opening bid of say 1, the program deals a number of hands that fit the auction to date. In this case, it deals hands where RHO opener bids 1, and the overcalling hand is known. After the deals are made, it assesses whether or not overcaller and partner might have a fit. Perhaps in this case overcaller holds Axx/Kxxxx/xxxx/x, and the sampling of deals suggests that on average, overcaller and his partner have an average heart fit of say 8.3 hearts.

With this information, those hands are passed through a double-dummy analyzer to see how the partnership fares in a heart contract, compared to the opponent's playing in their contract. Here, the program will probably decide that it gains more by bidding and playing 1 than by letting the opps play in 1, so overcaller will bid 1.

However on 'close' decisions, depending on the sample of hands, overcaller MIGHT decide to pass with this holding. That means that Buff might 'change it's mind' on a rebid. On some auctions, it might decide to bid, or pass, or double depending on the sample of simulated deals. The auctions are much more cluttered, the opponents more active, and some bids might seem unusual or aggressive, but are not so goofy that you wouldn't see them made in a typical matchpoint game. It's fun. The program finds lots of penalty doubles, and some of them will make, but many will not. It might bid one more even expecting to go down, if that score will be better than letting the opponents play their contract.

The bidding will not be instant, because Buff 'thinks' about the bids.

Not all bids are simulated. In highly conventional, tightly defined sequences, for example Stayman sequences, the bidding remains rule-based. Here, you have the option to establish the approximate 'thinking time' for simulation bids. The TOOLBAR allows you to extend the thinking time, stop the thinking, and switch Simulation bidding on or off.