In all cases, it is assumed that your partnership opens a strong 1NT, that is 15-17 HCP.

Let us suppose that your partner opens 1NT and RHO overcalls 2 (natural).
Without playing Lebensohl, these are the bidding tools that you have at your disposal.

• 1NT(2)-Double
  Penalty.
• 1NT(2)-2
  To play. Remember that transfers are off over interference.
• 1NT(2)-3 or
  1NT(2)-3 or
  1NT(2)-3
  Natural and game-forcing.
• 1NT(2)-3*
  The Q-bid is game-forcing Stayman. Opener will rebid 3NT without a holding of 4 or more spades.
• 1NT(2)-3NT
  Natural and game-forcing.
• 1NT(2)-2NT
  Natural and invitational.

Once you realize that a natural 2NT can never exist, you are half-way towards understanding Lebensohl.

Instead, we use a bid of 2NT to describe hands which cannot be handled by the above structure. Don't you wish you had a way of competing in a suit below the rank of the overcalled suit? How about some natural invitational bids? Welcome to the fruits of Lebensohl.

Here is the new structure:

• 1NT(2)-Double
  Penalty (no change).
• 1NT(2)-2
  To play (no change).
• 1NT(2)-3 or
  1NT(2)-3 or
  1NT(2)-3
  Natural and game-forcing (no change).
• 1NT(2)-3*
  The Q-bid is game-forcing Stayman (no change), but this sequence tends to deny a stopper in the enemy suit (see below).
• 1NT(2)-3NT*
  Natural and game-forcing (no change), but this sequence tends to deny a stopper in the enemy suit (see below).
• 1NT(2)-2NT*
  Lebensohl. Opener is forced to bid 3 and then responder will describe his hand further.
  • 1NT(2)-2NT*-3*-Pass or
    1NT(2)-2NT*-3*-3
    To play. Any bid after the Lebensohl relay below 3 of the overcalled suit is signoff.
  • 1NT(2)-2NT*-3*-3*
    Natural and invitational. Any bid after the Lebensohl relay above 3 of the overcalled suit is invitational. Why? Because we already have shown two sequences to describe a game-forcing hand with spades and a signoff hand with spades. There aren't any other possibilities.
  • 1NT(2)-2NT*-3*-3* or
    1NT(2)-2NT*-3*-3NT*
    What do you think these sequences should show? The standard agreement is that the slow Q-bid is still game-forcing Stayman and that the slow 3NT is still natural and game-forcing. The main difference is that this sequence shows a stopper in the opponent's overcalled suit. (Hence the mnemonic "slow shows.")

1. Craig Barkhouse once suggested to me that the invitational and game-forcing responses should be switched and I think that's a good idea. The theory is that (on average) you will hold more game-invitational hands than game-forcing hands when you play 15-17 notrumps. More utility translates into better scores.

   Unfortunately, the down-side is that when you do hold a game-forcing hand, your side will often be guessing which game should be played.

2. A lot of people play Lebensohl over a 2 overcall. The obvious disadvantage is that you can't slow-show a stopper and bid game-forcing Stayman by using Lebensohl. The other (and perhaps greater) disadvantage is that you lose all of your notrump structure by playing Lebensohl over 2.

   Bridge theorists agree that sequences starting with an opening bid of 1NT are the best to have. The opener has described their hand very accurately and the responder has a lot of control in placing the final contract because so much structure already exists. They can use Stayman, Jacoby transfers, Texas transfers, minor suit Stayman, and fragment bids to name a few. Why give up on your whole system for something worse? If you do, then I promise to overcall 2 against you every time you sit as my right-hand opponent. Promise.

   My personal preference is to play that a Double of the 2 overcall is Stayman and the rest of my system is on. This way is better than submitting to the damage that the overcall was attempting to do.

Because reverses are forcing to the 3-level, opener should have a king more than opening values (i.e. 16+) to reverse. If opener has a bare 16-17 (i.e. not enough to force to game opposite a minimal response), then responder should have the means to apply the brakes if they also have a minimal response.

The reverse auctions are:

• 1-1-2
• 1-1-2
• 1-1-2
• 1-1-2

In standard systems, responder's rebid of the fourth suit is natural and game-forcing. In order to apply the brakes, responder rebids his suit or 2NT. When playing Lebensohl over reverses, this doesn't change, however, 2NT is now Lebensohl and can never be passed.

In the following sequences, we will examine the first of the listed reverse auctions: 1-1-2.

• 1-1-2-3 or
  1-1-2-3 or
  1-1-2-3 or
  1-1-2-3 or
  1-1-2-3NT
  Natural and game-forcing (same as standard).
• 1-1-2-2
  Natural and nonforcing (same as standard).
• 1-1-2-2NT*
  Lebensohl. This bid is forcing.
  • 1-1-2-2NT*-3*
    The completion of the relay to 3 shows a minimal reverse. Responder now completes the relay sequence in a similar manner to Lebensohl over 1NT.
    • 1-1-2-2NT*-3*-Pass or
      1-1-2-2NT*-3*-3* or
      1-1-2-2NT*-3*-3*
      Just like in Lebensohl over 1NT, these bids are all signoffs.
    • 1-1-2-2NT*-3*-3* or
      1-1-2-2NT*-3*-3NT*
      What do you think responder was up to? He showed a weak hand and got a weak response from opener and then did something impossible. Responder must have a slam-try opposite a minimal reverse.
  • 1-1-2-2NT*-3* or
    1-1-2-2NT*-3* or
    1-1-2-2NT*-3* or
    1-1-2-2NT*-3NT* or
    1-1-2-2NT*-4*
    But what if opener has a game-forcing hand? He hardly wants to be passed out in 3 when he holds the values for game. The solution is to bid something other than 3.

• (2)-Double-2*
  To play. Definitely not a hand to be proud of.
• (2)-Double-2NT*-3*-Pass or
  (2)-Double-2NT*-3*-3* or
  (2)-Double-2NT*-3*-3*
  To play. Again, not a hand to write home about.
  Just like using Lebensohl over reverses, the doubler can bid something other than 3 to show a good hand.
• (2)-Double-3* or
  (2)-Double-3* or
  (2)-Double-3*
  Definitely shows some competitive values. If I had to assign a number, I would guess around 8 or 9.
  Just like using Lebensohl over reverses, if responder uses Lebensohl as a relay and follows up with 3, then this should be a try for slam.

The other sequences are the same as described above.

There are two other auctions where I typically play Lebensohl.

• (1)-Double(2)-?
  Whenever the opponents bid and raise a suit through partner's takeout double, 2NT is never natural. It can only be Lebensohl.
• (1)-Double(2*)-?
  If the opponents are playing weak jump shifts, then Lebensohl is almost a requirement to get back the room you've already lost by their ferocious bidding.