Romex system

The Romex system is a contract bridge bidding system designed by the Mexican bridge expert George Rosenkranz. Key features of Romex are the multiple meanings attributed to certain bids, namely the Dynamic one notrump and the Mexican two diamonds.

Dynamic one notrump

The dynamic one notrump opening indicates either:

The most common responses to the dynamic one notrump opening are:

Higher level responses indicate control count.

A consequence of the use of the dynamic notrump is that the 1NT rebid by opener becomes wide-range (typically 12-16 hcp). With game invitational values or better, responder reacts to such a rebid with a 2♣ checkback convention to ask opener to further describe his hand.

Mexican two diamonds

This opening indicates one of four hands: