|If partner responds in any of your four card suits there is no problem but if the response is in the suit of your singleton which, of course, is the more likely, life is not so straightforward. There are two cases to consider; firstly, when the opener has 12 – 14 points and secondly, with 15 or more points. In the former case a NT rebid is barred because that would show 15 or more points depending on the level of the NT bid so the rebid must be in a suit but, to repeat the suit opened would guarantee a five card suit and to bid a different suit would infer that the first bid suit is five cards long, both of which would be untrue. Unfortunately, there is no alternative but, hopefully, arriving in a 4-3 fit is not the end of the world. When opener has 15 points or more the situation is not so bad since, if responder bids your singleton, you can now rebid in NT without telling a lie about your strength.