If you want to Read Part I..[ilink url=”http://csbnews.org/new/promoting-tricks-in-defence-part-ii-by-terence-reese/?lang=en”].Click Here[/ilink] , there you will find Part I too
In the handling of the trump suit itself there are numerous ways in which defenders can come to extra tricks. One of the best known is the refusal to overtrump in a position such as the following:
Refusing to Over-Ruff
 A 7 J 6 5 3 K 7 6  A 8 5 2 |
||
| J 8 5 3 10 9 10 5 2 K 9 6 3 |
Q A K Q 8 9 8 4 3 Q 10 7 4 |
|
| K 10 9 6 4 2 7 4 2 A Q J J |
Against a contract of Three Spades the defenders start off with four rounds of Hearts. Declarer trumps the fourth round with the 10; it would be bad play for West to over- ruff, even though he does not know about his partner’s Queen. So long as West discards on this trick he comes to two tricks in trumps. Many players miss the right line when they have a chance, which they should refuse, to Over-rufï the dummy.
| 10 | ||
| 8 4 | K J 7 2 | |
| A Q 9 6 5 3 | ||
This is the trump suit and declarer ruffs a side suit with dummy’s 10 of trumps. If East overtrumps, he makes only two tricks in the trump suit; but if he discards instead of overtrtimping, he can make three tricks in trumps. There are innumerable variations of this play.