In any defensive bidding situation – where you believe the opponents to own more strength – your partnership should bid to the level of the fit. Take this example (Neither vul)

Presume partner for three diamonds.

• In (i), there is a nine-card fit, so bid for nine tricks – 3 ♦ .
• In (ii), there is a ten-card fit – 4 ♦ .
• In (iii), there is an eight-card diamond fit, but your partnership have already bid to the eight-trick level.

Look at it another way. Your partner thinks you have five diamonds and has bid to the presumed level of the fit on that basis. For each diamond you have above five, you should bid up an extra level. Take this example (Neither vul)

• In (iv), you have one more spade than the five promised, so should go one level higher than partner’s 3 ♠.
• In (v), you have no more than the five spades promised. Further, the flat, defensive nature of your hand make it clear to pass.
• In (vi), whilst you have no more than the five spades already promised, your 5521 shape with very little defence strongly suggest bidding 4 ♠. Use the level of the fit as the main criterion to decide how high to bid, but don’t be a slave to it.

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