Partner responds 1 ♠ and you are just about to rebid lNT (15-16 balanced) when right-hand opponent bids 2 ♣. Drat - you can no longer bid 1 NT. Many players now make the mistake of rebidding 2 NT, but that shows 17-18 balanced: just as it would after 1 ♥-(P)-1 ♠-(P)-2 NT. You should instead pass 2 ♣-partner is still there. He knows you have opened the bidding, so will not pass lightly.

Exercise: You open 1♦, partner responds 1♠ and right-hand opponent bids 2 ♥ as an overcall. What now with these?

• (i) Bid 3 ♦. Just as you would in 1 ♦-(P) -1♠-(P)-3 ♦. By being a jump over partner's 1 ♠ response, you are showing 16+ points and six diamonds.
• (ii) Pass. Not 3 ♦. As we see in (i), bidding 3 ♦ means the same whether or not the opponent bids 2 ♥: ie 16+ points.
• (iii) 2 ♠. You cannot bid 2 NT - that would show 17- 18. But although you were planning to rebid lNT (which you cannot now do), you can be somewhat flexible and try 2 ♠. It may be a 4-3 fit, but passing seems a bit supine.