These two-bids were conceived by Mr. Hugh Kelsey and Mr. Tom Culbertson. The essence of the concept is: 2 Hearts and 2 Diamonds are Multi openings, which become clear after a series of relay responses. See the following chart for the general partnership understanding, which has been varied over the years:
After a 2 - 2 is a relay or the cheapest bid. Responses are:
After a 2 - 2NT is the relay or cheapest bid. Responses are:
Some partnerships have the understanding that an opening also of 2 Hearts is understood to show also a 5-card Heart suit and an unnamed (not unspecified) 5-card Minor suit, an unbalanced holding, and only 6 to 10 high card points as with the 2 Spades opening. This is by partnership agreement.
It is also possible that a 2 Diamonds opening could be Roman Two Diamonds showing a strong three-suiter, but this is by partnership agreement.