THE ARTIFICIAL ONE-CLUB OPENING
Shows at least 17 points in high cards ( Goren 4, 3, 2, 1 count) or a strong distributional hand; does not show a club suit; is forcing for at least one round.
RESPONSES: The first response shows controls held (ace=two controls; king=one control) as follows:
1 NO TRUMP=FOUR
2 NO TRUMP=SIX OR MORE
Alternative response of 2 hearts and 2 spades show six-card suit with no controls; 3 hearts and 3 spades, seven-card suit; 4 hearts and 4 spades, eight-card suit. Since the opening bid announces at least 17 points, the first response sets the minimum level of the final contract at a game bid if it shows three or more controls. An overcall complicates the control-showing process, but in most cases does not change the responder's obligation to show his high cards. Without a control, he passes; with one control, he makes the cheapest available bid. For example, if the overcall is 1 heart, a pass says "no control"; a bid of 1 spade declares one control, etc. High interference bids make matters difficult, but are dangerous against the powerful hand shown by the one-club opening.
OTHER OPENING BIDS AND RESPONSES
One of any suit except clubs: at least four cards in the suit; 12 to 17 points.
RESPONSES: Pass with less than 6 points, but make effort to bid if better able to support opener's possible second suit. Raise or bid 1 no trump with minimum hand. Response in new suit is forcing for one round. Responder's first bid may be a short suit if the second suit he bids is higher-ranking. Second suit must be playable. A jump raise in opener's suit is not forcing; shows 9-12 points, four or more trumps.
A Jump response of 2 no trump is not forcing; shows 11-12 points; used only when the holdings promise some advantage if no trump contract is played from responder's seat.
ONE NO TRUMP: 12-17 points, five cards in clubs, no other long suit. Responder bids 2 clubs with a weak hand and at least 2 (usually 3) clubs.