Dummy play in Bridge is mostly routine play unless it poses a challenge that calls for ingenuity and skill. Not everyone in Bridge thinks alike but when options become available, Bridge thinking differs amongst even the best players resulting in either a big loss or gain.
Our first illustration is from a Rubber Bridge Game where with NS vulnerable and NS having a part score of 40, the bidding went as under with the NS hands given below:

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North
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K 10 8 6
A 8 5 2
A 8
A 10 4
========

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South
=============
A Q J 9 7 5 4
7 6 4
-
J 9 8
=============

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S    W     N    E
=================
-    -    1C   1D
1S   2D   2S   3D
3S   4D   4S    P
P    5D   Dbl   P
5S   P    P     P
=================

After a fierce competitive bidding NS in 5S receive the opening lead of a low diamond from west. If you are south, how do you play your play in 5S?
On the face of it with 7 trump tricks in hand and 3 side aces, there are 10 tricks available. From where do you chalk out the 11th trick to make the contract? Of course a heart can be discarded on the AD and if hearts break 3-3 the contract can be made, failing which there is yet one other alternate for the contract to make, and that is if just one of the club honours is held by west.
Did you go for the heart break or the split club honours? Well if you did either, you will still fail to make the contract for east held both club honours and west held K J 10 9 of hearts.
Yet even after such an adverse distribution with the west east hands as follows:

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West                 East
=========================
2                       3
K J 10 9              Q 3
10 7 6 4 3 2    K Q J 9 5
5 2             K Q J 6 3
=========================

Can you now, spot the winning line? It is of course easy to go wrong as did the actual declarer who after taking the AD on which he discarded one of the hearts and after trump extraction when he gave up a heart, west took it and switched to clubs and the declarer had to concede 2 club tricks and a heart for 1 down which hurt NS more, as 5D doubled was going 2 down for + 300.
Yet the contract as the cards lie be can be made. How? By just playing low from dummy on the diamond lead to discard a heart from hand. Now on the AD, another heart is discarded and west can never get the lead to play clubs. The timing of the play becomes crucial fornow when hearts are tested, with 2 ruffs in hand, the position of the remaining cards is as under:

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North      West       East         South
========================================
K 10 8     -          -          Q J 9 7
8          K          -                -
-          10 7 6 3   K Q 9            -
A 10 4     5 2        K Q 7 6      J 9 8
========================================

The stage is now set for end playing east by simply running the 8 of clubs towards east.
There is nothing east can do stuck with either giving ruff and sluff by playing diamonds or playing back a club towards declarer's A10 in dummy.
The play was not too difficult if declarer had visualized that the contract can be made even if the club honours be in one hand. By the way playing the AD at trick 1 was still not altogether fatal for declarer can ruff a diamond, draw a round of trumps, then play ace and another heart. Supposing west wins and exits with a club, east will still be stuck with the lead, end played to hand declarer the 11th trick and the contract. A look at the bidding should have given south a clue. East's hand was not less than an opening hand which given EW the split heart honours tilted the balance of having KQ of clubs with east rather than being split. The contract was not guaranteed. But there was a better way to play.