(dummy, visible to all players). West and East hold the remaining four spades KQ32 in their two closed hands. Prior to play, 16 different West and East spade holdings or "lies" are possible from the perspective of South. These are listed in Table 1, ordered first by "split" from equal to unequal numbers of cards, then by West's holding from strongest to weakest. South leads a small spade, West plays the 2 (or 3), dummy North plays the J, and East wins with the K. Later, after winning a side-suit trick, South leads another small spade and West follows low with the 3 (or 2). At this point, with North and East yet to play, the location of only the Q has not been established. South is at a decision point and knows that only two of the original 16 lies remain possible (bolded in Table 1), for West has played both low cards and East the king. At first glance, it may seem that the odds are now even, 1:1, so that South should expect to do equally well with either of the two possible continuations. However, the principle of restricted choice tells us that while both lies of the cards are possible, the probabilities are 2:1 in favour of assuming West holds Q32 and to therefore play the ten. If East had KQ, he could equally well have played the queen instead of the king. Thus some deals with original lie 32 and KQ would not reach this stage; some would instead reach the parallel stage with K alone missing, South having observed 32 and Q. In contrast, every deal with original lie Q32 and K would reach this stage, for East played the king perforce (without choice, or by "restricted choice"). If East would win the first trick with the king or queen uniformly at random from KQ, then that original lie 32 and KQ would reach this stage half the time and would take the other fork in the road half the time. Thus on the actual sequence of play, the odds are not even but one-half to one, or 1:2. East would retain queen from original KQ about one-third of the time and retain no spades from original K about two-thirds of the time. The principle of restricted posits that to finesse by playing the 10 is nearly twice as likely to succeed. Importantly, this