A "reverse" is part of standard bidding. All bridge players use it, whether they realize it or not. Understanding reversals is good for your bridge, your health and your safety.
So What is a Reverse?
Opener: Provided your partner has responded at the 1-level, the requirement to bid a new suit at the 2-level that ranks higher than your first suit, is 17+ points.
Reversing implies greater length in your first suit (usually 5-4, but maybe 6-4 or 6-5.) Reverses are forcing for one round.
All of North’s second bids are reverses:
North South North South North South
1♣ 1♥ 1♥ 1NT 1♦ 1♠
2♦ 2♠ 2♥
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Here, North’s rebids are NOT reverse bids:
North South North South North South
1♣ 1♥ 1♥ 2♣ 1♥ 1♠
1♠ 2♠ 2♣
North’s 2nd suit South's 2♣ bid Clubs rank lower
is on the 1-level. shows 11+ points. than hearts.
is on the 1-level. shows 11+ points. than hearts.