SAYC. Overcalls show 8-16 points (double and bid the long suit with a stronger hand).SSS. An overcall is not a point-count bid. An
overcall shows and offensively-oriented hand with a good suit and substantial playing strength, and often contains shortness in an unbid suit. You must take the level of the overcall and your vulnerability into account. At worst,
an overcaller should expect to go down no more than three tricks facing a worthless dummy---no more than two if vulnerable. There are four reasons for overcalling:
(1) You have a good hand and think the deal may belong to your
side in the suit you bid.
(2) You have a distributional hand and think your side may have a profitable sacrifice in the suit you bid.
(3) You think partner may wind up on opening lead and want him to lead
your suit.
(4) You want to take away bidding space from your opponents.
Notice that nowhere does the word "points" appear in my account of overcalls. Because of (3), certain "points" should influence you to pass rather
than overcall in close cases. Kings and queens in unbid suits, for example, should make you less eager to have your partner lead your suit if he winds on opening lead, for you figure to do just able as well if he leads his own
suit, but when your only strength is in your suit you should be especially eager to have partner lead it. Notice that overcalls in different suits are far from equal. Some overcalls, such as 1C-1S and 1D-2C take away bidding space
from the opponents; others, such as; 1C-1D, 1D-1H and 1S-2C don't. Because of (4), I'll bid 1S over a 1C opening on hands where I wouldn't dream of bidding 1D with a similar suit; likewise, I'll bid 2C over a 1D opening on hands
where I wouldn't dream of bidding 2C over a 1S opening. I'll overcall more freely when I hold spades than other suits because spades give me a better chance of buying the contract than any other suit: you can fight lower-ranking
suits with higher-ranking suits much more successfully than you can fight higher-ranking suits with lower-ranking suits. If you have spades and they have hearts, and each side can make the same number of tricks, the deal belongs to
your side (1); not so if you have hearts and they have spades. If the hand belongs to your opponents, who can make 4H, you are more likely to have a profitable save in spades (you need only bid 4S) than clubs or diamonds (you must
bid 5C or 5D).
When you have a good hand and a good long suit, don't double an opposing opening bid---jump in your suit. This "strong jump overcall" promises playing strength appropriate to the level of your jump: 7 to
8 winners at the 2-level, 8 to 9 winners at the 3-level. If you double, the
opponents, or your partner, may bid at a level that makes it unsafe for you to bid your long suit later. To double then jump in your suit requires a
stronger hand still.
ADVANCING OVERCALLS. Note: to distinguish the partner of INTERVENOR (overcaller or doubler) from the partner of OPENER, we call opener's partner RESPONDER but intervenor's partner ADVANCER.
SAYC. The only
forcing "response" is a cue bid, which asks overcaller to rebid his suit without jumping if he has a minimum (at most 10 or 11 points), or make some other descriptive rebid with extra strength (at least 11 points). New
suits are non-forcing, usually denying a fit. Cue
bids are game-forcing. Other bids are defined by point-count ranges, single raises as 6-11 points with at least 3-card support, double raises as 10-12 points with at least 4-card
support, 1NT as 9-12 points, 2NT as 11-13 points but 13-15 points if a jump, 3NT as 15-16 points.
SSS. A cue-bid is forcing, implying a fit; overcaller rebids naturally (11 or 12 points do NOT constitute extra strength). A jump
in another suit suit is forcing but does not imply a fit. New-suit bids are constructive but not forcing. All raises and notrumps are limit bids.