Source: The Bob Crosby Memorial Library
D.S.I.P.: Do Something Intelligent Partner (Haz algo Inteligente Compañero); En todos estos articulos LHO= jugador a su izquierda y RHO= jugador a su derecha)
Sacrificing is an art rather than just a Bridge skill. Beginning Bridge players sacrifice too much in IMPS giving the opponents a “fielders choice” of doubling rather than take their iffy games. In fact , a tactic by good players is to deliberately bid close games vulnerable against non vulnerable bidding opponents to induce a pseudo sacrifice. Pseudo sacrifices are a very bad Bridge result.
There is an analytical side to sacrificing. Taking the vulnerability into consideration , there is simple arithmetic to do. You are not vul against vul and it is certain that they will make their game you have 500 to “play with” . In fact for the tactical advantage of making them bid again at the 5 level and possibly go down , you have 800 to play with . 800-650=150 is not an IMPS disaster as it is in matchpoints. Equal vulnerable sacrifices are more rare but still possible. Quite often the decision is straight arithmetic. How many tricks does the auction dictate that we will take on defense against what we take on offense ? The law of total tricks helps on these decisions. Add up your total trump that your side holds and if it adds up to 10 , go for the 10 trick game. Tom Gandolfo had a sacrificing decision against the Barton team recently.
Q109xxx 
xx 
Axx 
Axx Tom opens 1 (NV) against (NV) and LHO doubles and partner bids 3 which shows 4 spades but not much else. They bid 4 so now what ? Law of total tricks says you have 10 trump so offensive action is encouraged. Does partner have two defensive tricks required to beat the hand ? Almost impossible on the bidding so bidding 4 is an easy decision. Even if you have miscalculated badly , this is IMPS and not matchpoints so –500 is not a horrible loss. 500-420=80 is not many IMPS. Turns out you go for –100 against their 420 for an excellent Bridge result.
There are tools of the trade to prevent bad sacrificing and those are forcing passes and D.S.I.P. double theory. If the opponents own the hand , a pass of their contract is a “green light” to suggest a sacrifice. Tom had a recent difficult situation in a sacrifice situation. The vul opponents against nv opened 1NT and Tom doubles with x QJx AQxx AQJxx and they make a punitive redouble. It is standard expert agreement to play 2 as a scramble in these situations. It means we do not have a 5 card suit or longer and not enough HCP’s to justify passing so lets scramble to our fit. If we do bid a suit , it must be 5 cards or longer and of course no values. Anyway I bid 2 and the opening NT bidder shows 5 spades by bidding 2. The doubler’s hand has now grown on this particular auction. In support of diamonds , it is huge as the opponents are bidding your stiff spade. You now bid 3 spades which shows your diamonds and your spade shortness . The vul opponents bid a confident 4 and now its my decision: xxx 10xx J1098x 10x. Partner has short spades and 16 HCP’s behind the 1NT bidder . Partner must have 4 defensive tricks outside the spade suit to beat 4 spades which is not likely. 5 will not get severely punished. In fact , if I could get to my hand , 5 goes for –100 against their +620. The key bid was anticipating that they might bid a vul 4 game by bidding spades to show your diamond fit and short spades to partner.
D.S.I.P. doubles were designed to prevent pseudo sacrifices. If you want to sacrifice or bid again with defense , you ask partners permission with a double . The auction goes 1-1 -2-2-4-P-P-? and you hold Kxx x Axxxx xxxx and with the opponents vul and you not a sacrifice might be a good idea. So you double saying you would like to bid but to cover the bases I also have defense. Partner has KQJxx Q109x xx Qx and converts your double for +500 . You go at least one down and probably two down in 4 spades ! The 1st double opposite a passing partner is D.S.I.P. in competitive auctions . Say for example , the spade overcaller wanted to bid 4 with defense. She would double and the other hand with their trump can convert. No pseudo sacrifices with D.S.I.P. theory !!