PSI Bridge Course Winter 2017-2018 Lecture 03 General remarks

Structure Types of bridge tournaments Last week’s match – results Trump suit – fit Planning 12/13/2017 Lecture 03

Some types of bridge tournaments N-S: fixed E-W: one table up Deals: one table down Mitchell (pairs) Howell (pairs) Teams match (teams of four) Complicated motion Directions are placed on each table 12/13/2017 Lecture 03

Scoring in Mitchell and Howell tournaments N-S ID E-W ID Contract & Result N-S points E-W points N-S deal points E-W deal points NS1 EW1 4SE= 420 3 NS8 EW7 NS7 EW5 3NTW+1 430 6 NS6 EW3 6SxE-1 100 For each pair: the scores are summed across deals and are normalised to the sum of points they would have made, had they been better than all competitors on all deals they played The pairs are ranked on the basis of their final percentage (performance) Average performance: 50% 12/13/2017 Lecture 03

Teams match (teams of four) 12/13/2017 Lecture 03

Last week’s teams match Room 1 Room 2 Total scores Contract TeamA TeamB TeamA – TeamB TeamA IMPs TeamB IMPs 3HN+3 230 6HN= 980 -750 13 2SW-1 50 1NTE+2 150 200 5 3NTS+3 490 3NTS+2 460 30 1 4HW= 620 3HW-1 100 720 -720 12 1NTN= 90 2HN-2 290 7 3NTE+1 630 3NTE= 600 -30 Team A – Team B: 13-26 12/13/2017 Lecture 03

Trump suit – fit Trumps are introduced so that the opponents cannot run their long suits Lacking the controls in all suits, it makes sense to investigate the possibility of a fit (eight cards in a suit between the two hands). Why? Your side holds more trumps that the opponents; control the trump suit  control the play The play with just one more trump (i.e., seven vs opponents’ six) is not comfortable, in particular as the most probable split with six missing cards is 4-2, not 3-3! The trial-and-error approach has shown that (at least) eight trumps make the declarer’s task considerably easier 12/13/2017 Lecture 03

Hypergeometric distribution (sampling without replacement) Useful split cases Let n trumps be missing; we are interested in their distribution (n-k,k) between the opponents’ hands Hypergeometric distribution (sampling without replacement) 5 cards missing 4 cards missing 3 cards missing 2 cards missing 5-0 3.91% 4-0 9.57% 3-0 22.00% 2-0 48.00% 4-1 28.26% 3-1 49.74% 2-1 78.00% 1-1 52.00% 3-2 67.83% 2-2 40.70% 12/13/2017 Lecture 03

Strategy and tactics  K 8 5  K Q 8 3  K Q 8 4  9 6  J 10 6 4  6 5 2  A K 10 7  A 9 7 3 2  J 10 4  J 9  Q J 2 3-4 4-4 2-4 5-4 6-4 8-5 1-4 7-4 7-5 0-2 0-1 1-2 1-3 One trick in spades Three tricks in trumps Ruff one spade in the dummy Three-four tricks in diamonds  Q  9 6 5 2  A 10 7 3  8 5 4 3 Important Play hearts from the dummy Ruff one spade before drawing all trumps Contract: 2 N 12/13/2017 Lecture 03

Helping the police with their investigation... The Elinescu - Wladow bridge-cheating scandal: https://www.youtube.com/watch?v=1xVj1EQ_vSI The Fantoni - Nunes bridge-cheating scandal: https://www.youtube.com/watch?v=TKe7gLTfaF8 The Fisher - Schwartz bridge-cheating scandal: https://www.youtube.com/watch?v=831tJ4EHLBY 12/13/2017 Lecture 03