My favourite bridge blog is Phillip Martin's The Gargoyle Chronicles. Not only is Phillip an excellent writer and player, his series of boards played with and against Jack has been compelling reading over the past couple of years. I recommend it to everyone, but I'm sure some of the analysis will be a little too deep for many.
As it happened, I was playing with and against robots yesterday and an interesting play problem did arise.
Press the Next button to see the opening lead and dummy.
It does not look too promising with two apparent diamond losers and nowhere to pitch them. In such cases thoughts often turn to squeezes, but ducking a trick to rectify the count looks both dangerous and difficult here. As East may have a singleton diamond you cannot duck the opening lead.
So second thought is an endplay of some form. If East has a singleton diamond, we may be able to throw him in with the third heart to give us a ruff and discard. Or he may have the doubleton ten of diamonds and fails to play it at trick one, then we can eliminate hearts and clubs to lead up towards the jack of diamonds: when East plays the ten, we duck giving the defence no winning play - this line requires a misdefence, although throwing the ten of diamonds at trick one may not be clear, and 7-2 hearts, not great odds.
It cannot hurt to draw the trumps and, surprisingly, West shows out on the first round. So East has (at least) six hearts and three spades!
Let's reconsider our thoughts. At favourable vulnerability GIB would probably have bid three hearts with 37(21), so it is relatively safe to place him with six hearts. If he is 3=6=3=1, then we can only make the contract if he has a singleton club honour. If he is 3=6=1=3, then we probably cannot make the contract.
If he is 3=6=2=2, then we can eliminate hearts, take two rounds of clubs (not three, to prevent him unblocking the ten of diamonds) and then play up to the jack of diamonds and hope he has doubleton ten.
However, hopefully you've spotted that there is another option if East is 3=6=2=2. In this case West controls both minor suits and can be squeezed without the count being rectified. This line also works whenever East holds 3=6=2=2, 3=6=3=1 (whatever the singleton) and those 3=6=1=3 distributions when West holds both club honours.
So the easiest line is to ruff out the hearts to confirm the position and then force West to unguard one of the minors by playing all your trumps. I expect he'll come down to the singleton queen of diamonds, so you concede this trick and win his club return to make the contract.
Press Next on the diagram to see the full hand.