Crash over 1NT

This is a defense convention against opponents 1NT opening.

• X = 2 suits of the same color (reds or blacks)
• 2 = 2 suits of the same rank (majors or minors)
• 2 = 2 suits of the same shape ( and , or and )
• 2M or 3m = natural Different variations are possible.

Note that this method is now illegal under the revised ACBL general convention chart.