Opponents interfere over our 1NT opening

After a Penalty DBL

After a Non-penalty DBL the system stays unchanged. RDBL is for business (usually less than game values).

After a level-2 overcall showing explicitly only 1 suit (either a 1-suiter or a 2-suiter with an un-known second suit)

After a 2-suited overcall showing explicitly both suits

After 2NT with a 2-suiter (usually the minors)

After a Natural Overcall at level 3

After a DBL of our Stayman 2C

After an overcall of our Stayman 2C

After a DBL of our 2D transfer bid (showing diamonds)

After a DBL of our 2H transfer bid (showing hearts)

After a DBL of our 2S transfer bid (showing spades)

After an overcall of our transfer bid