In Competition

1♣ - (pass) - 1♦/♥ - (dbl) -

pass    =    11-13, no 3 card support, RE redoubles with 10+ 

1♥/♠     =     11-13, 3 card support

rdbl    =    17-19 balanced, no ♦/♥ ST

1NT    =    17-19 balanced, ♦/♥ ST

2♣    =    natural

2♦ (also cue)    =    4 card  support , 17-19 balanced or 17+ unbalanced, system on or asking for stopper (if cue)

2♥ (cue)    =    F1, asking for ST; Control if later bids above 3NT

2♥/♠    =    11-13, 4 card  support 

3♦    =    14-16, unbalanced, 4 card  support

3♥/♠    =    11-13, unbalanced, 4 card  support