The powerful feature that not only tells you whether you might have been in a better contract but also suggests where a different line of play would have made (or broken) the contract.
Here's a deal where South is in four hearts and West's opening lead is the JS :
South ducked the opening lead, won the second round of spades and led a heart to the 10. The KC came next, won by West, who switched to the 9D, covered in turn by the queen, king and ace. South led a heart to the jack and cashed the QC to leave this position with North on lead :
The AH was cashed and South ruffed a spade back to hand to draw West's last trump but West over-ruffed. With a certain loser in diamonds, South finished one down. Unlucky, or was it ? Fortunately, South was playing Blue Chip Bridge, now equipped with Hindsight, which reported :
South watched as Blue Chip Bridge demonstrated the winning line on-screen. Ruff the spade with the KH, cash the JC (discarding North's 6S) and then lead over to North's JD. Now exit with a diamond to East's 10. Whichever black card East leads, South ruffs with the 8H and West's trumps are caught in a smother coup.
And here's an example of how Hindsight can help you with your bidding :
Playing Acol with a weak no-trump, what would you open as South on the hand below ?
South decided to open 1S and rebid 2NT over North's 2C response. North raised to 3NT but the defence took the first five tricks in diamonds and South was quickly one down. At the end of the play, Hindsight displayed the following message :
As Hindsight shows, it was South's choice of opening bid that led to N/S ending up in the wrong game contract. After the recommended opening bid of 1H, N/S would have had no trouble in reaching the easy 4H contract. The best that the defence can do is to take two quick diamond tricks and hope for a third trick with the queen of trumps.
That's the power of Hindsight. Wouldn't you like to have it ?