Rumpelsohl by Paul van Rijckevorsel was published in The Bridge World,
October 1992. Traditionally, (2x) X also start Lebensohl. However, artificial
calls, even limited ones, are not meant to be passed with boring hands. I
decide to modify the bidding structure for this subtle difference. There are
several reasons to invite with 2NT.
Bidding to (2x) X is not free.
An invitational X usually lacks a stopper.
Therefore, 2NT includes non-forcing clubs or balanced invitational hands.