After three rounds of bidding, and having shown a basic minimum hand, I decide to double opponents on what appears to be a misfit. I feel safe in the knowledge that partner cannot assume it as takeout because opponents have shown all four suits (including the one I originally bid) plus I have denied a fit in partner's major.
However, North GIB thinks for a while. Then decides to take out to 4♦. I must say North showed restraint in bidding only 4 because I made exactly FOUR tricks .
Well done, GIB. Minus 600 instead of Plus 300/500.