Defense system after opps 1NT opening
Trash (TRAnsfer or SHape) allows you to describe all one or two suited hands usually at the two level, to allow either partner to show extra strength, and retains a penalty double by either partner. I learned the system from a local expert (Tampa Florida) who claims Trash originated from Harold Feldheim. The system doesn't seem to appear in any of the standard references such as Kearse's. (Ron Klinger's "Bridge Conventions, Defenses and Countermeasures" does describe a similar but hideously complicated system.) Trash can also be played after 2NT, over either strong or weak notrumps. After 1NT:
dbl - for penalty
2C - transfer to diamonds, or 10 cards in hearts and spades
2D - transfer to hearts, or 10 cards in spades and clubs
2H - transfer to spades, or 10 cards in clubs and diamonds
2NT - transfer to clubs, or 10 cards in diamonds and hearts
After advancer (the overcaller's partner) accepts the transfer:
pass - weak one-suited hand
next suit - weak two-suited hand
raise - invitational one-suited hand
jump shift - invitational two-suited hand
(Note: no hand should be too weak; this is an overcall after all!)
2S - 10 cards in clubs and hearts, or 10 cards in diamonds and spades
Advancer bids 2NT to find out which hand; with the round suits (clubs and hearts) you will rebid 3C. With the pointy suits (diamonds and spades) you will rebid 3D.
With very strong hands you can make the Trash bid one level higher. Or if advancer is very strong he can accept the transfer by bidding one level higher, or by refusing to accept the transfer (e.g., 1NT - 2C - P - 2H or 2S or 2NT or 3C). If you find requiring 10 cards for the shape bid is too restrictive, you can agree instead that a shape bid shows at least 9 cards in the two suits.
I like Trash because the regular structure reduces memory lapses, because both partners can penalty double, because I can show any one or two suited hand, and because both overcaller and advancer can show different strength ranges.
Besides, it's fun to be able to claim "We play Trash overcalls!"