Even experienced players can get confused (or forget) when it comes to opener's jumpshifts and reverses.
Opener's Jumpshift is GF. That means a really big hand. Responder cannot pass and the partnership cannot stop below game. The range is roughly 18+ (maybe 19+) points (counting useful distribution*).
Here are all of opener's possible jumpshifts into a new suit:
1
-1
-2
1-1-2
1-1-2
1-1-2
1-1-3
1-1-3
1-1NT-3
1-1-3 or 3
1-1NT-3 or 3
1-1NT-3 or 3 or 3
Any other jump by opener would not be a GF jumpshift. Here are the other possible (single) jumps opener can make (none of these are GF jumpshifts):
1-1-2NT (Natural + balanced, 18-19, not forcing)
1-1-3 (A jump rebid -- natural, invitational about 16-18 in playing strength)
1-1-3 (A jump raise -- Natural, 4-card support, invitational about 16-18 in playing strength)
1-1-2NT (Natural+balanced, 18-19 not forcing)
1-1-3 (Natural, 6+ diamonds, about 16-18 in playing strength)
1-1-3 (Natural, 4-card support, about 16-18 in playing strength)
1-1-2NT (Natural+balanced, 18-19 not forcing)
1-1-3 (Natural, 6+ diamonds, about 16-18 in playing strength)
1-1-3 (This is a "jump-reverse" which is a strange animal to be discussed at the end of this article)
1-1-3 (Natural, 4-card support, about 16-18 in playing strength)
1-1-2NT (Natural+balanced, 18-19 not forcing)
SUMMARY OF ABOVE:
If opener jumps into a new suit, it is natural and GF. It is usually not a balanced hand (they would have jump rebid 2NT or opened 2NT). If opener jumps to 2NT it shows 18-19 balanced. If opener jumps in a previously bid suit (by either opener or responder) it shows a good hand (16-18), but is only invitational. Jump raises, jump rebids and jumps to 2NT are not GF. They are not even forcing at all. Though it is not a jump, I wish to point out here that if the response to any opening bid is 1NT and opener's rebid is 2NT, that shows 18-19 balanced (1any-1NT-2NT).
Reverses
Opener's reverse is not forcing to game. But, it is forcing one round. Responder should not pass opener's reverse. The range is about 17-20 (counting playing strength). Click the link for specifics, but the gist of opener's reverse is:
Opener's second bid is (not a jump) in a higher ranking suit than his first-bid suit. We are concerned only with auctions where responder bid on the one-level. If responder responds on the two-level, don't think of reverses. So, these are opener's possible reverses:
1-1-2
1-1-2 or 2
1-1NT-2 or 2 or 2
1-1-2
1-1NT-2 or 2
1-1NT-2
Rather than memorize the bidding sequences in this article, just know the definitions. Once you know that a reverse is 1X-1Y-2Z where Z is a higher-ranking suit than "X" you will recognize it. Remember that a reverse is a strong bid, forcing, but not GF. Occasionally, I hear (newer) students proudly state: "I don't play reverses." That's nice, but don't be proud. Like it or not, if you produce one of the auctions above, you have reversed! Try not to do it unless you have a strong hand!
Lastly, we have a strange animal that should be avoided except in very serious partnerships. That is a "jump reverse." Because a reverse is forcing (and up to 20), there is never a need to jump and reverse. Why preempt your own strong auction? So, these auctions make no sense:
1-1-3 (2 would be a big bid, so no need for 3)
1-1-3 or 3 (again, no need to jump when a reverse would suffice)
1-1-3 (2 is forcing, so no need for 3)
Why make such a bid? Experienced partners (who study and remember) use this as a "mini-splinter." It shows 4-card support, about 16-18, and shortness in the suit jumped in. It shows not quite enough for a 4-level splinter raise. So, 1-1-3 would show something like:
KQ106
2
A65
AQ652.
*"Playing strength" means HCP + useful distribution. Don't add for shortness in partner's suit, but add for useful long suits and useful short suits.
