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Kaplan Interchange/Inversion Relay
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Over a 5+ 1 opening, some people play Kaplan Interchange (KI) where 1 shows a negative NT with 0-4 and 1NT shows 5+, both forcing. Most see it as an alternative to Flannery, making it easier to handle opener's hand with 5+ and 4. Another popular convention is a 2 response to a major, most typically showing a GF with a balanced hand or clubs (but some play it as GF which could contain any shape).

In this article I will explain a modification of KI me and my partner has been playing for a while. 1--1NT still shows 5+ spades, but 1-1 shows either a forcing NT with 0--4, or a GF hand (typically balanced). Now your 2/1 bids could all show a 5+ suit, and you could even make them non-forcing if that's a style you're comfortable with.

You will not be able to play 1NT after a 1 opening, but this is most often the case playing regular KI too. Opener's rebids after 1 looks like this:

  • 1--1;
  • 1NT = 4+ or any unbalanced hand with extras (about 16+)
  • 2 = Natural. Could be a three card suit if balanced. Minimum (about 11--15).
  • 2 = 6+. Minimum.
  • 2 = 5-6 majors.
  • 2NT = 18--19 NT.
  • 3 = 5 card suit, medium strength (about 13--15)
  • 3 = 7(+), medium strength

So we basically have a Gazzilli structure. Limiting opener's hand early makes the continued bidding easier.

If responder is weak his rebid will be about the same as after a forcing NT; usually passing, inviting, or giving preference. Over opener's 1NT responder bids 2 in order to show spade preference (in case opener has the "weak" hand).

What will responder do if he's strong? Read on.

Opener's most common rebids are 1NT or 2. I won't discuss continuations after higher rebids here, since they should be pretty easy to figure out. The key to this method is to use responder's 2 rebid as an artificial, GF relay. This is okay since responder can not have spades. Over 1NT though we use 2 as the relay, but more about that later.

  • 1--1; 2m--2;
  • 2NT = No shortness. 3 relays again and 3 shows 5422, other 5332.
  • 3 = 5 and 4 card minor + shortness somewhere. 3 asks shortness.
  • 3 = 5+ minor suit. 3 asks shortness.
  • 3 = 6, 4m. 3 asks shortness.
  • 3 = 0-5-4-4 (opener has rebid his better minor)

When opener has 6+ (and usually single-suited, since we tend to prefer showing our minor side suit if 6-4), 2 is still the relay:

  • 1--1; 2--2;
  • 2NT = No shortness. You could play that 3 asks three-card suit (and 3NT would show 7222).
  • 3 = Singleton minor suit.
  • 3 = Singleton spade suit.
  • 3 = Void.
  • 4 = Void.

The principle is that we try to find out general shape (side-suit or single-suiter) and if opener has shortness somewhere. We also rebid 2NT without shortness, which seems natural(?).

Next up: Opener's 1NT rebid.

When opener rebids 1NT he shows either 4+ or a hand with extras (about 16+). This is similar to Gazzilli/Häxan, but one step lower. Responder can relay with 2 in order to force game vs the 16+ hand, but also have other options:

  • 1--1; 1NT---
  • 2 = Relay, about 8+ (GF vs 16+)
  • 2 = Spades preference. Opener usually bids 2 with strong hand, but could also support spades or make a natural rebid.
  • 2 = Heart preference.
  • 2 = 0--1, 3. Both minors or 6+. Now 2NT asks longer minor, while 2 is a preference.
  • 2NT = 5-5 minors, 0--1, 0--2
  • 3 = 6+, 0--1
  • 3 = 6+, 0--1, 0--2
  • 3 = Limit raise

If responder relays, opener will describe his hand:

  • 1--1; 1NT--2;
  • 2 = GF with a 4+ minor
  • 2 = Minimum (11--15) with 4. 2 is a preference, 2NT relays and 3M invites.
  • 2 = GF with 4.
  • 2NT+ = GF with 6+, same principle as after 1--!1s; 2--2 (see previous page)

We continue our relay journey when opener rebids 2, and you'll see that we can re-use a lot from the previous page:

  • 1--1; 1NT--2; 2--2;
  • 2 = 4+ clubs and shortness somewhere. 2NT relays and same principle as 3+ below.
  • 2NT = 5422 (no shortness). 3 asks which minor.
  • 3+ = Same principle as after 1--1; 2m--2. So 3 shows a 4 diamonds, 3 5+ diamonds, 3 6-4, and 3 0-5-4-4.

The new stuff really is when opener has 4 spades. We can relay with 2NT in order to find out more. If opener make the strong rebid (2) you can raise the major instead, or bid 3m, to limit your hand. You're still in a game force.

  • 1--1; 1NT--2; 2M--2NT;
  • 3 = Singleton
  • 3 = 4-5-2-2
  • 3 = 4-5-4-0
  • 3NT = 4-5-0-4
  • 4 = Void, 6+ and 4

So we've finished this relay craziness. From here you should probably have a way to set the trump suit, but I will not go into that in this article. A tip is to check out the Mulberry (or 4/4/RKC) convention though, which would probably work here. You instead use a control asking and spiral cue bids if that's your style.

What should you do after 1--1NT? I'm not sure, but perhaps 2 could be Gazzilli and others natural (with 2 potentially being 2-5-3-3)? I'll leave that for you to discuss!

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