Overview of the MileHigh 2 Diamond
Opening 2
is very strong
We have re-tasked the opening 2
to show a balanced 18-19 HCP hand. A strong hand, but not a powerhouse.
This results in our redefining an opening 2♦ from a weak 2 bid to now be our bid with a hand too strong
to open 2NT and/or too strong to let our partner pass with <6 HCP. Almost, always, a game forcing hand.
When you hold a 9+ trick, suited hand. One caveat is that you should not have 3 'quick losers' in your hand. That could be a 3-card side suit without any honor. Or, a hand with XX and X in side suits. Those hands will bid better with a 1-level opening bid. Since you are lacking in total HCP, either your partner can respond or the opponents will balanced to give you another bid.
Responding to 2
The responses to the opening 2♦ are pretty straight-forward. They mostly depend on the control cards (Aces and Kings) in your hand and whether you have a long suit.
We use both 2♥ and 2♠ as waiting bids. These show hands with 0 or 1 control card and indicate this is your longest major. Your longest major could be 2 cards up to 5 cards. The concept is convey minimal strength (i.e. no interest in slam, but may support a game try). Additionally, if the opener has a powerhouse single-suited hand it is unlikely to be in the responder's longest suit. This mostly keeps the responder from 'stealing' the contract and make the strong hand come down on the table as dummy.
After the waiting bid, the opener will bid 2NT to show a 22-24 HCP balanced hand. Any other bid, shows a self-supporting suit for trump and the ability to take 9+ tricks with it as trump.
Responding with 2NT indicates that you hold length in both majors. You are asking the opener to bid their preferred one. This bid tells the opener that your hand won't play well in No-Trump. If they still choose a NT contract, their hand will come down and dummy.
Bids at the 3-level show positive controls.
3♣ shows two control cards (AA, AK or KK). It functions like Puppet Stayman and asks the opener to show their major suit shape.
3♦ and 3♥ function as a solid transfer to hearts. The hand has 2 control cards and at least 5 cards in the transfer suit
3♠ is our super positive. This bid shows 3 control cards (at least AKK). This requirement is because our 3NT bid, described below, is used for hands with exactly 3 Kings.
3NT shows exactly 3 Kings (no Aces). This bid 'steals' the No-Trump contract from the opener, but ensures protecting the Kings from the opening lead if the defense happened to hold an AQ tenace bracketing the King.