Here are some problems I faced in the Mini-Blue Ribbon Pairs playing with Mike Develin. All problems are at matchpoints.
(A) All white
LHO opens 3H, partner overcalls 3S, and RHO passes. What's your call?
(B) All white, matchpoints
Partner opens 1S. RHO overcalls 2H. What's your bid / plan?
(C) All white
LHO opens 1C, partner overcalls 1NT, and RHO passes. You can:
-bid 2H (transfer to spades)
-bid 2S (to show an invite with diamonds)
-bid 3C (weak transfer to diamonds)
-bid 2C (Stayman; pulling 2H to 2S shows an invitational hand with 5 spades)