Verlau 2004
1§/2§(Strong)
DBL=© + ª
1¨=5+¨
1©=5+©
1ª=5+ª
1NT=§ + ¨
2¨=A weak MAJOR
2¨-2©=Pass/correct
2¨-2ª=Pass/correct
2©=© + a minor
5-4 either longer
2ª=ª + a minor
1§(Variable)
2¨=© + ª