If you wish, you can open 2NT (or open 2♣ and rebid 2NT) with a hand containing a small singleton. You can open one of a suit and rebid 1NT or jump rebid 2NT with a small singleton. You can overcall 1NT or 2NT with a small singleton.

Do you need a balanced hand to open 2NT?

To open 2NT you should try to ensure that you can control all your suits by having an honor card in each. Notrump openings show a balanced hand and can be made with a five-card major suit or a five-card minor suit.

Can you open 1NT with a singleton ace?

The change allows players to open 1NT with hands that include a singleton ace, king or queen, as long as they do not also contain a doubleton.