When I am filling in as the spare player on one of my Diamond Bridge Holidays, I always play whatever system my partner feels most comfortable with.
I always hope for a simple system since complicated conventions usually lead to disaster. However, there are a few conventions without which I feel as if I am playing with one hand tied behind my back.
When a recent partner came out with the statement “I don't play fourth-suit forcing, I have found it never comes up,” I felt that fate was being tempted and, sure enough, I was soon confronted with a bidding problem that had no solution:
As South I wanted to bid the fourth suit to say, “Partner, I know we should be going further, but I have nothing clear-cut to bid at this stage.” However, we had agreed that 2

would be a natural call, so I had to come up with an alternative.
Both 2

and 3

would have been non-forcing (and would have promised a six-card suit), and to bid clubs or diamonds certainly did not look right, so eventually I just closed my eyes, crossed my fingers, and bid 3NT.
West led the

5, which I ducked in the dummy. East returned another round of hearts, and West, with no outside entry allowed the dummy to win the trick.
I could now see two spade tricks, one heart trick, one diamond trick and two club tricks, so I had to find three extra tricks from somewhere without letting West win a trick. The club finesse was the obvious source of one, and the spade suit seemed the most sensible hope for more; after all, I just needed East to hold

Qxx!
Pursuing this slim hope, I cashed the

A, took the club finesse, and then played the

K, and a small spade. When East emerged with the holding I was hoping for, I was home and dry.
In the post-mortem, West berated her partner for not defeating the contract. Before reading on, can you see what he could have done to defeat me?
If on the second round of spades East had played his queen, it would have given West the vital entry in the spade suit with her

10, so that she could get in to cash her hearts.
However, since we were playing duplicate pairs, where overtricks can make such a difference, I don’t think that East could be criticised for not throwing away his

Q. At rubber or teams, though, I would expect that many strong players might well find the winning line. Would you?