Bridge base basic, also known as BBO basic, is a bidding system

Bidding system

A bidding system in contract bridge is the set of agreements and understandings assigned to calls and sequences of calls used by a partnership, and includes a full description of the meaning of each treatment and convention...

 for the game of bridge

Contract bridge

Contract bridge, usually known simply as bridge, is a trick-taking card game using a standard deck of 52 playing cards played by four players in two competing partnerships with partners sitting opposite each other around a small table...

 based on Standard American Yellow Card. It is simplified, suitable for beginners, and widely used in internet bridge particularly on Bridge Base Online

Bridge Base Inc.

Bridge Base Incorporated is a company founded in 1990 by Fred Gitelman, President, and Sheri Winestock, Vice-President and based in Summerlin, Nevada....

. It is taught in Fred Gitelman

Fred Gitelman

Fred Gitelman is a leading American bridge player, as well as the founder and manager of , a bridge playing site....

's educational software called Learn to Play Bridge that is available as a free download from the American Contract Bridge League

American Contract Bridge League

The American Contract Bridge League is the largest contract bridge organization in North America. It promotes the game of bridge in the United States, Mexico, Bermuda, and Canada, and is a member of the World Bridge Federation...

's website.

Key points of BBO Basic Bidding

Like SAYC, BBO basic depends upon hand evaluation using the high card point method. Hand shape adjustments are made for long suits (1 point additional for every card longer than 4 in a suit) when bidding a new suit, and for short suits when showing support for partners bid (5 for a void, 3 for a singleton, and 1 for a doubleton).
Other similarities to SAYC include:

• Five-card majors
  Five-card majors
  Five-card majors is a contract bridge bidding treatment which is very powerful and standard in modern bidding systems, including Standard American, Bridge Base Basic, and 2-over-1 game forcing...
  
  : opening a major suit promises a five-card suit.
• Weak two bid
  Weak two bid
  The Weak two bid is a common treatment used in the game of contract bridge, where a jump bid of two of a suit signifies a weak hand with a long suit. It is a form of preemptive bid...
  
  s: Two diamond, heart or spade openers are made with a six-card suit and 6 to 10 high-card points. Two of the top 3 honors are promised in that suit.
• Strong two clubs
  Strong two clubs
  In most natural bridge bidding systems, the opening bid of 2 is used exclusively for hands too strong for an opening bid at the one-level. Systems that incorporate a strong 2-club opening bid include modern Standard American, standard Acol, 2/1 game forcing and many others...
  
  : An artificial 2 call promising 22 points or more.
• Pre-emptive openers: including weak three bids (all suits except no-trump) and Weak four bids (minor suits only) similar to the weak two bids but showing additional length.
• Notrump openers show a balanced hand (no void, no singleton, at most one doubleton, and may include a 5 card major) with the following point ranges:
  • 1 NT = 15 to 17 points
  • 2 NT = 20 to 21 points
  • 3 NT = 25 to 27 points
• Stayman and Jacoby transfer
  Jacoby transfer
  The Jacoby transfer, or simply "transfers", in the card game contract bridge, is a convention initiated by responder following partner's notrump opening bid that requests opener rebid in the suit ranked just above that bid by responder, i.e...
  
  s conventions for no-trump openers
• Blackwood
  Blackwood convention
  In the partnership card game contract bridge, the Blackwood convention is a popular bidding convention that was developed by Easley Blackwood. It is used to explore the partnership's possession of aces, kings and in some variants, the queen of trumps, to judge more precisely whether slam is likely...
  
   or Gerber
  Gerber convention
  Gerber is a contract bridge convention devised by Dr. William Konigsberger and Win Nye from Switzerland who published it in 1936; John Gerber of Texas introduced it to North America in 1938 where it was named after him...
  
   for slam bidding.

Opener approximate hand strengths

For unbalanced hands:

• 0 - 12 points: Pass unless the hand is suitable for a preemptive opening bid.
• 13 - 21 points: Hands of 13 points or more are strong enough to open with natural bidding, including:
  • minimum opening hands with 13-15 points
  • medium opening hands with 16-18 points
  • maximum opening hands with 19-21 points
• For unbalanced hands with 22+ points: show a very strong opening hand by using the strong 2 convention.

For balanced hands, open with a no-trump bid when you can limit your hand to the following point ranges:

• 1NT = 15-17 HCP
• 2NT = 20-21 HCP
• 3NT = 25-27 HCP

For other balanced hands, you can still limit your points by opening in your longest suit and then using the no-trump bid on your second bid:

• 13 - 14 HCP: bid 1 of a suit and then make a non-jump rebid in no trump (1NT)
• 18 - 19 HCP: bid 1 of a suit and then make a jump rebid in no trump (2NT)
• 22 - 24 HCP: bid 2 and then make a non-jump rebid in no trump (2NT)
• 28 - 30 HCP: bid 2 and then make a jump rebid in no trump (3NT)
• 31 - 32 HCP: bid 2 and then make a double-jump rebid in no trump (4NT)

Responder approximate hand strengths

The responder also communicates hand strength through bidding by responding to partner's opening bid uniquely according to their high card points.

• 0-5 points: A hand in this range normally should not bid (i.e. should pass) unless partner opens with the strong 2 convention.
• 6-9 points: This is a minimum response hand. You can show support for partners bid with a simple raise to the 2-level, bid a new suit if you can do so at the one-level, or respond 1NT otherwise.
• 10 or 11 points: any new suit bid at the 2-level promises opening partner at least 10 points. With specifically 10 or 11 points, you have a medium strength hand, and can bid another 4-card suit but at the two-level now in hopes of discovering the 8-card fit. You plan eventually to invite partner to a game contract.
• 12 or more points: you have a maximum hand and desire a game contract. You have the bidding space available to search for a fit and share additional information that may help find a slam if possible.

Responding with a minimum hand

1. First priority is to show 3 card support for a partner's 5 card major, respond 2 of the major with 6-9 points. Bidding 4 of the major immediately is preemptive and shows 6-9 points with 5 card support and at least 1 singleton or void in a side suit.
2. Next priority is to bid your longest suit at the 1-level, promising 6-9 points and at least 4 cards in that suit. Do not go to the 2-level with less than 10 points.
3. Show support for partners minor suit opening if you have 5 card support (4 card support is acceptable but not preferred) by responding 2 of the minor. Bidding 4 or 5 of the minor is preemptive and shows 6-9 points with 6 card support and at least 1 singleton or void in a side suit.
4. When you cannot support your partners bid, then your response is 1 NT, to show a bad fit and no more than 9 points (i.e. you deny ability to raise or bid a new suit). This gives partner the choice of passing and playing in 1 NT or changing to a partial game in another preferred trump suit (partner knows you are going to pass because you previously said you have 6-9 points).

Responding with a medium hand

1. First priority is to show 3 card support for a partners 5 card major, so rebid partners suit at the 3 level. This limit raise is skipping the possible bid at the two level and jumping to the 3 level specifically to indicate that you have 10 or 11 points, an 8 card fit in partners major trump suit, and you are inviting your partner to a game bid if he has more than minimum opening strength. (opening bid promised a minimum of 13, and you have 10 or 11 for a sum or 23 or 24 points, very close to the game level of 25 points)
2. Next priority is to bid your longest suit.
3. Show support for partners minor suit opening with 5 card support (4 card support is acceptable but not preferred) by responding 3 of the minor.

Responding with a maximum hand

Your partnership should be in a game-level contract when you include your minimum 12 points with partners promise of 13. Unlike SAYC where a strong jump shift is recommended, you show a very strong hand in BBO Basic using the "principle of slow arrival." This means keeping the bidding low and showing support for partners suit with two sequential bids:

1. Bid another suit first at the lowest level, show a long or a strong suit.
2. With your second bid, show support for partners suit. Even if partner supports your first bid, remember to bid your partners suit to indicate you have the 8-card fit and game level points.

Responding with Balanced Hands

A no-trump response to partners opening bid gives point information limited in values

• response of 1NT means you have 6-9 points and no support for partners suit and no possible 4 card bid to make;
• response of 2NT means you have 13-15 points and no support for partners suit and no possible 4 card bid to make;
• response of 3NT means you have 16-18 points and no support for partners’ suit and no possible 4 card bid to make.

Opener's response to partners search for a fit

Often after opening with a natural bid in the 13-21 point range, the responder will suggest a new suit at the one level. While this promises 6 points or more, it leaves a gap in the information to make the optimum contract.
If opener has 4 card support for responders new suit, then opener should show support but also therefore has the burden of showing his hand strength to partner so that responder can choose the best contract:

• minimum opener (13 to 15 points): respond at the 2 level
• medium opener (16 to 18 points): respond at the 3 level, inviting game
• maximum opener (19 to 21 points): respond at the 4 level

Examples (showing only partnership bids with no interference):

• 1-->1-->2-->pass (both partners had minimum hands but found the fit)
• 1-->1-->3-->pass (opener had extra points and invited game, but responder had only a minimum hand)
• 1-->1-->4-->pass (opener had game values)
• 1-->1-->2-->4 (opener had minimum hands but responser had game going points)
• 1-->1-->3-->4 (opener had extra points and invited game, and responder had extra points and accepted)