Overcall Structure

Caltech Version

Basics:

There are 3 basic parts to the overcall structure. 1NT as a 3-suited takeout (No-Trump for Takeout or NTO), Power Doubles, and Roman jump overcalls showing specific 2-suited hands. The more aggressive point range for these overcalls is 6⁺ NV and 8⁺ Vul. To be sounder, we can use lower-bounds of 6/8/10/12 at increasingly unfavorable vulnerability. Some of the overcalls are unlimited, but most are capped at about 15 or so. Use discretion when overcalling with minimal hands.

1NT for Takeout:

Promises 6/8/10/12-15 points, with 3⁺ cards in each of the unbid suits and 2 or fewer in the bid suit. As a matter of partnership style, decide if you will bid 1NT with a 5-card major in preference to bidding the suit at the 1 level.

Responses without interference:

Cuebid is Stayman with a good hand
Pass and 3NT are natural, recalling their stoppers must be lead through
2NT shows the lowest two unbid suits
all other hands bid to the law level in their long suit, assuming 3 from partner

After interference over 1NT, double is responsive up to 3

(or 4

, 4

raises). New suit bids are natural.

Runout after 1X-1NT--?

bid a 5 card suit (their suit is also natural)
shows 4 cards in the highest unbid suit (usually )
2NT shows the two lowest unbid suits, preemptive
all others pass

After advancer’s

, 1NT bidder bids a known fit if any, or 4+ card suits up the line.

After advancer’s pass, 1X-1NT-

-P-P-?

bids are 5 card suits
denies 5 card suit, asks advancer to bid 4-card suits up the line.

Power Doubles:

15+ pts, usually balanced (needs 17-18+ for singleton or void in doubled suit)

Reponses to 1X-

-P-?

pass with 4 reasonable trumps and 8+
1 level suit bids show 4 card suits - optionally the cheapest 1-level suit (if available) is negative (0-4).
1NT 5-7 (no stopper needed) (may be weaker over 1-)
2NT 7-9 (stopper)
3NT 9-? (stopper)
2X Cuebid game forcing
jump to 2Y invitational with 5 card suit

Direct Overcalls:

Cheapest bids of new suits over 1X are normal (7-16 usually 5⁺ suits at the 1 level, 10⁺ and a good 5⁺ suit at the 2 level), although they deny the desire to make 3 suited 1NT or 2 suited jumps. This means that if they have a 2^nd suit worth mentioning, it will be lower ranking and hence easier to rebid. Direct overcalls tend to have somewhat more length in either opener’s suit or their own suit as a negative inference from failure to bid 1NT.

Roman Jump Overcalls:

6/8-15 (or 6/8/10/12-15). A single jump shows two adjacent suits - the suit bid and the higher ranking suit, 5⁺ in the lower and 4⁺ in the higher suit. So 1

-2

shows 5

. The only tricky ones are 1(

)-2

which shows 5

since clubs is “higher” than spades, but not higher ranking. Jumps forcing to the 3 level, such as 1

-3

(showing

) should be at least 5/5 shape. With equal length in two suits, consider bidding the higher ranking suit at the one level (if possible), hoping to rebid your second suit naturally.

Random Note: 1

-2

is not needed as a Roman Jump, and is just a regular weak 2 bid.

Responses – (these apply to cuebids as well)

Raises in either known suit – competitive
Cue Bid – strong game invitation
2NT – invitational with 3 cards in higher of partner’s suits
4^th suit bids – to play

Cuebids:

6/8⁺ (or 6/8/10/12⁺). Unlimited two suited hands (at least 5/4 in the lower/higher ranking suits), with the two suits adjacent to the suit cuebid. Ex. 1

-2

shows 5/4 or better in

2NT:

A strong two suited hand (at least 5/4 unspecified), with 4½ losers or less. Shows the suit not adjacent to the suit bid and another unspecified suit. For example, 1

-2NT shows spades and either clubs or hearts.

Other Jump Overcalls (Preemptive):

Jumps that are higher than what is needed to show a 2-suited hand are normal preempts. 3-level cuebids are stopper asks for 3NT.

4 level Overcalls:

Overcall structure uses Namyats 4 level overcalls, although this is not GCC legal. For GCC events, these bids are natural and preemptive.

Cheat sheet for overcalls up to 3

Your Bid over...	1	1	1	1
	15+ bal.	15+ bal.	15+ bal.	15+ bal.
1	natural
1	natural	natural
1	natural	natural	natural
1NT	3 suit takeout 6-15	3 suit takeout 6-15	3 suit takeout 6-15	3 suit takeout 6-15
2	+ (5/4) 6+	natural	natural	natural
2	+ (5/4) 6-15	+ (5/4) 6+	natural	natural
2	+ (5/4) 6-15	+ (5/4) 6-15	+ (5/4) 6+	natural
2	weak 2 bid	+ (5/4) 6-15	+ (5/4) 6-15	+ (5/5) 6+
2NT	+ ? strong (4/5,5/4)	+ ? strong (4/5,5/4)	+ ? strong (4/5,5/4)	+ ? strong (4/5,5/4)
3	stopper ask for 3NT	preemptive, natural	+ (5/5) 6-15	+ (5/5) 6-15
3	preemptive, natural	stopper ask for 3NT	preemptive, natural	+ (5/5) 6-15
3	preemptive, natural	preemptive, natural	stopper ask for 3NT	preemptive, natural
3	preemptive, natural	preemptive, natural	preemptive, natural	stopper ask for 3NT