Overcalling 1NT

That expression causes endless confusion – and I’ve finally worked out why (I think). In Bridge players’ jargon, “overcalling 1NT” means “bidding 1NT as an overcall”. 

The confusion arises because it is perfectly natural to interpret the expression “overcall 1NT” to mean: bid at the two-level as an overcall over the opposing 1NT. This is not what “overcall 1NT” is intended to mean in “BPJ” (Bridge Players’ Jargon). 

Bidding as an overcall over the opposing 1NT is not really much different to bidding as an overcall over an opening such as 1 ♠. You’d have a good five/six card suit and at least about eight/nine points at the (very) low end.

To bid 1NT as an overcall, you should have 15-18 (or 19) points, balanced with a stopper in the suit opened.

After your right-hand opponent opens 1 ♠, you would bid 1NT as an overcall (“overcall 1NT”) with these hands:

Hand A: Bid 1NT
Hand B: Bid 1NT, a better description than 2♦.
Hand C: Double - for take-out. Do not bid 1NT as an overcall because you have no spade "stopper".