10. Return Leads by Third hand Against NT

Normaly third had should return partner's suit but if a switch is called
for, proper card should be selected:
(1) Holding a broken sequence and missing card in the dummy, treat that
    card in your hand and lead top of the sequence
(2) Holding a doubleton, don't lead an honor but lower card. It promises
    that you can stand a return of the same suit.
     
        6xx             E should lead a 2 and not a 10, in which case, W
        -----           after taking the A on the K can safely lead back the
AJ8x    |W  E| 102      suit. If E leads back 10, W can't lead back the suit
        -----
        KQ97

(3) Normally lead by third had is in a suit weak in dummy, but lead may be
    made to the strength of dummy, if you can win tricks if returned by
    partner later gaining an entry
(4) Avoid leading a new suit with Qxx as it may promote declarers' trick.

        Jxx                   Return of a low card by E gives a sure trick
      ------                  to S. If S has to play the suit himself, he
A108x |W   E| Qxx             gets no trick 
      -------
       K9x


       Jxx
       ----                   Return of a low card by E gives S two tricks. If 
K98x  |W  E|Qxx               S has to play the suit himself, he gets only one
       ----                   trick
       A10x