1♥ (promising 4+ ♠)
Pass
2♠
? Now what
I confess that it is often very tough for the player sitting 4th to balance or not on borderline hands. To get this thread going, how about starting with the much easier decisions? We will get to the tougher ones later.
So for starters:
Hand 1: A 3-suited takeout double
At this point it is not clear what South will do next, even with his minimum count.
E/W can take make 9 tricks in ♣.
If E/W botch up the defence, 3♠ is going to make.
South will probably up the ante with his distribution and nice ♠ suit.
The defence will need to draw trumps every time they get in to stop the ♦ ruffs.
Hand 2: Leaping Michaels
Before actually presenting the hand, some pointers from the system notes
1. In some cases, responder may chose to make a single raise holding a balanced hand with 4-card ♠ support and between 3-5 HCP.
2. The advantage of allowing the raise to 2♠ on this hand type is that partner cannot be passed out in a 3-card ♥ fit with an eight card ♠ fit available.
3. Bidding like has dangers of its own (which I have no intention of mentioning here)
So this hand qualifies for the 3-5 HCP single raise with 4-card trump support.
Hand 3: 2NT for the Minors
MOSCITO may easily gain here if E/W can't find the ♦ slam. An alternative would be for East to jump to 4NT with a hand like this to ensure that at minimum, game is found.