2 What reversing means

Reversing is not a crime. Misusing the reverse is the crime. To reverse simply means bidding a higher-ranking suit after a lower one, e.g. 1D - (1NT) - 2S.

That’s a reverse, is it wrong? It all depends on the strength of the hands.  The reason why we need care with reversing is this: partner has to show preference and if they prefer the first suit, which is most of the time, then we are at the dreaded three-level.  Without a paddle if we are minimum, but if stronger?  Since getting nine tricks needs one whole trick better than minimum, opener needs an extra ace, or 4 extra points equivalent.

So now we see that deliberate reversing of this sort needs (and shows) 16 points - this may be useful in nudging partner into 3NT.

And there’s always the harmless 1C - 1D - 1H- 1S I quoted in my first tip.

So, a low reverse is OK, a high reverse is strength-showing.

When responder sees partner reverse at the 2-level, she should not hesitate to show preference at the 3-level; this is no show of her strength, it is partner who has the strength. Qu: I have 5 diamonds and 4 spades and 12 points. I open my longest suit, 1 diamond, correct? (Ans: yes) and my partner goes 2 clubs. If I bid my second suit spades now I will have done a high reverse, probably forcing my partner to the 3-level over my 12 points. So what can I do? (Ans: repeat your diamonds with gritted teeth because repeating one’s first suit ideally shows 6 cards. Why bid the spades anyway, you know your partner hasn’t got four spades.) Do I? (Ans: Tell you later.)