Lebensohl...the best of both worlds... 

Interference in NT sequences tend to wreck havoc with most "Standard" styles of bidding.  After 1NT...2H  Holding KJxxxx...7...J632...xx  How do you "compete"?  2S?  You really don't want to let the opponents have the bid for 2H....but that 2S call could put partner on a guess if there isn't a clear cut understanding (and you really don't want to hear another bid by partner!)  Holding KJxxxx...x...Qxx...Qxx   you want to invite game...add the Ace of H...now you want to "Force"  game.  How do you help partner distinguish between these types of hands?  Lebensohl to the rescue!

LEBENSOHL AND THE PRINCIPLE OF FAST AND SLOW ARRIVAL

Lebensohl adheres to the style of "Fast/Slow arrival" where an immediate bid, shows a weaker hand than a "delayed" sequence bid.  The strength inferred in the delayed sequence is a stopper in the opponents bid suit.  The delay is accomplished by a "Puppet" sequence where the responder bids 2NT...transfering the opener to 3C...now the responder is able to clarify their intentions.  This "puppet" feature allows additional  definition to suit bids, Stayman and NT Game bids.

"SASS"=Slow Action Shows Stopper  or  Slow Auction Shows Strength

GENERAL INFO: 

A 2 level bid is natural and non-forcing...1NT...(2C) partner bids  2D or  2H  or  2S they are saying STOP!

An immediate 3 level bid is natural and 100% Game force!

A "puppet" delay of  (2N....3C) ....followed by a bid in your suit is invitational ...ONLY   WHEN YOUR SUIT IS HIGHER RANKING THAN OPPONENT'S! In the auction that goes...

1N...(2H)...2N...3C...then responder bids 3S...it is Invitational...because 2S and 3S were available...

* (If your suit is lower ranking than opponent's...the invitational  bid is lost..only  "STOP" or "FORCE" bids available!

                                1N...(2S)...2N...3C...3H is a STOP bid....Because 2H was not available....

                                1N...(2S.)..3H    becomes a Forcing bid

Of course if your private partnership is more comfortable reversing the meanings of these two bids to adhere to the fast vs slow arrival principle...go for it!

A cue bid is "Stayman" 

A direct bid of 3NT or Stayman denies a stopper in opponents suit... 

A "Puppet" delay followed by a Stayman bid or 3NT shows a stopper...

                                1N...2H...3N.........=I have game points but no H stopper!

                                1N...2H...2N>3C...3NT=I have game points and a H stopper!

                                1N...2H...3H.........=I have 4 Spades but no H Stopper!

                                1N...2H...2N>3C....3H=I have 4 Spades and I have a H stopper!

DOUBLES OF THE OPPONENT’S BIDS... 

"X" of opponents 2 level "Natural" bid is "Penalty"  in nature...

"X" of opponents 3 level "Natural" bid is "Take-out" in nature...

"SASS" is off after an artificial bid showing 2 suits!

 However the main principles of Lebensohl do still apply after an artificial bid:

                1NT..(2C...showing Hearts and Spades)....2D says STOP....3D is Forcing ...

                1NT..(2C...showing Hearts and Spades)...2NTis still a “puppet” to 3C

"X" of artificial bid shows a willingness to penalize one or both suits shown!

CUE BIDS OF THE OPPONENTS BID SUIT...

If opponents bid is "Artificial" showing  2 KNOWN suits...Cue bid one of  their suits to show a Stayman   type of  hand...the cheapest level cue bid you can make is an "Invitational" Stayman bid and the higher level bid is a "Forcing" Stayman bid!  If the bidding goes...1NT...(2D showing Diamonds and Hearts)   then 3D would be Invitational...3H  would be Forcing...

If  a 2-suited Artificial bid only  names .one  KNOWN  suit...then cue bid of the known suit is Stayman...

A cue bid of an Artificial bid is Natural...7+pts..1 round Force...NOT 100% game force..

                1NT...(2¨...showing Hearts and Spades)......3¨=Shows Clubs, 7+ pts, 1 Rd Force

Hold...Q87...J3...A654...Q732   The bids are 1NT...2D...?